title: Adrian Carton de Wiart

text: A good part of Carton de Wiart's reporting had to do with the increasing power of the Chinese Communists. The journalist and historian Max Hastings writes: "De Wiart despised all Communists on principle, denounced Mao Zedong as 'a fanatic', and added: 'I cannot believe he means business'. He told the British cabinet that there was no conceivable alternative to Chiang as ruler of China." He met Mao Zedong at dinner and had a memorable exchange with him, interrupting his propaganda speech to criticise him for holding back from fighting the Japanese for domestic political reasons. Mao was briefly stunned, and then laughed.


title: Adrian Carton de Wiart

text: After the Japanese surrender in August 1945, Carton de Wiart flew to Singapore to participate in the formal surrender. After a visit to Peking, he moved to Nanking, the now-liberated Nationalist capital, accompanied by Julian Amery, the British Prime Minister's Personal Representative to Chiang. A visit to Tokyo to meet General Douglas MacArthur came at the end of his tenure. He was now 66 and ready to retire, despite the offer of a job by Chiang. Carton de Wiart retired in October 1947, with the honorary rank of lieutenant-general.


title: Adrian Carton de Wiart

text: En route home via French Indochina, Carton de Wiart stopped in Rangoon as a guest of the army commander. Coming down stairs, he slipped on coconut matting, fell down, broke several vertebrae, and knocked himself unconscious. He was admitted to Rangoon Hospital where he was treated. His wife died in 1949. In 1951, at the age of 71, he married Ruth Myrtle Muriel Joan McKechnie, a divorcee known as Joan Sutherland, 23 years his junior (born in late 1903, she died 13 January 2006 at the age of 102.) They settled at Aghinagh House, Killinardrish, County Cork, Ireland.


title: Adrian Carton de Wiart

text: Carton de Wiart died at the age of 83 on 5 June 1963. He left no papers. He and his wife Joan are buried in Caum Churchyard just off the main Macroom road. The grave site is just outside the actual graveyard wall on the grounds of his own home, Aghinagh House. Carton de Wiart's will was valued at probate in Ireland at £4,158 and in England at £3,496.


title: Adrian Carton de Wiart

text: Carton de Wiart is the subject of the 2022 song "The Unkillable Soldier" by Swedish heavy metal band Sabaton on their album "The War to End all Wars".


title: Ribosome

text: Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to form polypeptide chains. Ribosomes consist of two major components: the small and large ribosomal subunits. Each subunit consists of one or more ribosomal RNA (rRNA) molecules and many ribosomal proteins (RPs or r-proteins). The ribosomes and associated molecules are also known as the "translational apparatus".


title: Ribosome

text: The sequence of DNA that encodes the sequence of the amino acids in a protein is transcribed into a messenger RNA chain. Ribosomes bind to messenger RNAs and use their sequences for determining the correct sequence of amino acids to generate a given protein. Amino acids are selected and carried to the ribosome by transfer RNA (tRNA) molecules, which enter the ribosome and bind to the messenger RNA chain via an anti-codon stem loop. For each coding triplet (codon) in the messenger RNA, there is a unique transfer RNA that must have the exact anti-codon match, and carries the correct amino acid for incorporating into a growing polypeptide chain. Once the protein is produced, it can then fold to produce a functional three-dimensional structure.


title: Ribosome

text: A ribosome is made from complexes of RNAs and proteins and is therefore a ribonucleoprotein complex. Each ribosome is composed of small (30S) and large (50S) components, called subunits, which are bound to each other:


title: Ribosome

text: The synthesis of proteins from their building blocks takes place in four phases: initiation, elongation, termination, and recycling. The start codon in all mRNA molecules has the sequence AUG. The stop codon is one of UAA, UAG, or UGA; since there are no tRNA molecules that recognize these codons, the ribosome recognizes that translation is complete. When a ribosome finishes reading an mRNA molecule, the two subunits separate and are usually broken up but can be re-used. Ribosomes are ribozymes, because the catalytic peptidyl transferase activity that links amino acids together is performed by the ribosomal RNA.


title: Ribosome

text: Ribosomes are often associated with the intracellular membranes that make up the rough endoplasmic reticulum.


title: Ribosome

text: Ribosomes from bacteria, archaea and eukaryotes in the three-domain system resemble each other to a remarkable degree, evidence of a common origin. They differ in their size, sequence, structure, and the ratio of protein to RNA. The differences in structure allow some antibiotics to kill bacteria by inhibiting their ribosomes, while leaving human ribosomes unaffected. In all species, more than one ribosome may move along a single mRNA chain at one time (as a polysome), each "reading" a specific sequence and producing a corresponding protein molecule.


title: Ribosome

text: The mitochondrial ribosomes of eukaryotic cells functionally resemble many features of those in bacteria, reflecting the likely evolutionary origin of mitochondria.


title: Ribosome

text: Ribosomes were first observed in the mid-1950s by Romanian-American cell biologist George Emil Palade, using an electron microscope, as dense particles or granules. They were initially called Palade granules due to their granular structure. The term "ribosome" was proposed in 1958:


title: Ribosome

text: Albert Claude, Christian de Duve, and George Emil Palade were jointly awarded the Nobel Prize in Physiology or Medicine, in 1974, for the discovery of the ribosome. The Nobel Prize in Chemistry 2009 was awarded to Venkatraman Ramakrishnan, Thomas A. Steitz and Ada E. Yonath for determining the detailed structure and mechanism of the ribosome.


title: Ribosome

text: The ribosome is a complex cellular machine. It is largely made up of specialized RNA known as ribosomal RNA (rRNA) as well as dozens of distinct proteins (the exact number varies slightly between species). The ribosomal proteins and rRNAs are arranged into two distinct ribosomal pieces of different sizes, known generally as the large and small subunit of the ribosome. Ribosomes consist of two subunits that fit together (Figure 2) and work as one to translate the mRNA into a polypeptide chain during protein synthesis (Figure 1). Because they are formed from two subunits of non-equal size, they are slightly longer in the axis than in diameter.


title: Ribosome

text: Prokaryotic ribosomes are around 20 nm (200 Å) in diameter and are composed of 65% rRNA and 35% ribosomal proteins. Eukaryotic ribosomes are between 25 and 30 nm (250–300 Å) in diameter with an rRNA-to-protein ratio that is close to 1. Crystallographic work has shown that there are no ribosomal proteins close to the reaction site for polypeptide synthesis. This suggests that the protein components of ribosomes do not directly participate in peptide bond formation catalysis, but rather that these proteins act as a scaffold that may enhance the ability of rRNA to synthesize protein (See: Ribozyme).


title: Ribosome

text: The unit of measurement used to describe the ribosomal subunits and the rRNA fragments is the Svedberg unit, a measure of the rate of sedimentation in centrifugation rather than size. This accounts for why fragment names do not add up: for example, bacterial 70S ribosomes are made of 50S and 30S subunits.


title: Ribosome

text: Prokaryotes have 70S ribosomes, each consisting of a small (30S) and a large (50S) subunit. "E. coli", for example, has a 16S RNA subunit (consisting of 1540 nucleotides) that is bound to 21 proteins. The large subunit is composed of a 5S RNA subunit (120 nucleotides), a 23S RNA subunit (2900 nucleotides) and 31 proteins.


title: Ribosome

text: Affinity label for the tRNA binding sites on the "E. coli" ribosome allowed the identification of A and P site proteins most likely associated with the peptidyltransferase activity; labelled proteins are L27, L14, L15, L16, L2; at least L27 is located at the donor site, as shown by E. Collatz and A.P. Czernilofsky. Additional research has demonstrated that the S1 and S21 proteins, in association with the 3′-end of 16S ribosomal RNA, are involved in the initiation of translation.


title: Ribosome

text: Archaeal ribosomes share the same general dimensions of bacteria ones, being a 70S ribosome made up from a 50S large subunit, a 30S small subunit, and containing three rRNA chains. However, on the sequence level, they are much closer to eukaryotic ones than to bacterial ones. Every extra ribosomal protein archaea have compared to bacteria has a eukaryotic counterpart, while no such relation applies between archaea and bacteria.


title: Ribosome

text: Eukaryotes have 80S ribosomes located in their cytosol, each consisting of a small (40S) and large (60S) subunit. Their 40S subunit has an 18S RNA (1900 nucleotides) and 33 proteins. The large subunit is composed of a 5S RNA (120 nucleotides), 28S RNA (4700 nucleotides), a 5.8S RNA (160 nucleotides) subunits and 49 proteins.


title: Ribosome

text: During 1977, Czernilofsky published research that used affinity labeling to identify tRNA-binding sites on rat liver ribosomes. Several proteins, including L32/33, L36, L21, L23, L28/29 and L13 were implicated as being at or near the peptidyl transferase center.


title: Ribosome

text: In eukaryotes, ribosomes are present in mitochondria (sometimes called mitoribosomes) and in plastids such as chloroplasts (also called plastoribosomes). They also consist of large and small subunits bound together with proteins into one 70S particle. These ribosomes are similar to those of bacteria and these organelles are thought to have originated as symbiotic bacteria. Of the two, chloroplastic ribosomes are closer to bacterial ones than mitochrondrial ones are. Many pieces of ribosomal RNA in the mitochrondria are shortened, and in the case of 5S rRNA, replaced by other structures in animals and fungi. In particular, "Leishmania tarentolae" has a minimalized set of mitochondrial rRNA. In contrast, plant mitoribosomes have both extended rRNA and additional proteins as compared to bacteria, in particular, many pentatricopetide repeat proteins.


title: Ribosome

text: The cryptomonad and chlorarachniophyte algae may contain a nucleomorph that resembles a vestigial eukaryotic nucleus. Eukaryotic 80S ribosomes may be present in the compartment containing the nucleomorph.


title: Ribosome

text: The differences between the bacterial and eukaryotic ribosomes are exploited by pharmaceutical chemists to create antibiotics that can destroy a bacterial infection without harming the cells of the infected person. Due to the differences in their structures, the bacterial 70S ribosomes are vulnerable to these antibiotics while the eukaryotic 80S ribosomes are not. Even though mitochondria possess ribosomes similar to the bacterial ones, mitochondria are not affected by these antibiotics because they are surrounded by a double membrane that does not easily admit these antibiotics into the organelle. A noteworthy counterexample, however, includes the antineoplastic antibiotic chloramphenicol, which successfully inhibits bacterial 50S and eukaryotic mitochondrial 50S ribosomes. Ribosomes in chloroplasts, however, are different: Antibiotic resistance in chloroplast ribosomal proteins is a trait that has to be introduced as a marker, with genetic engineering.


title: Ribosome

text: The various ribosomes share a core structure, which is quite similar despite the large differences in size. Much of the RNA is highly organized into various tertiary structural motifs, for example pseudoknots that exhibit coaxial stacking. The extra RNA in the larger ribosomes is in several long continuous insertions, such that they form loops out of the core structure without disrupting or changing it. All of the catalytic activity of the ribosome is carried out by the RNA; the proteins reside on the surface and seem to stabilize the structure.


title: Ribosome

text: The general molecular structure of the ribosome has been known since the early 1970s. In the early 2000s, the structure has been achieved at high resolutions, of the order of a few ångströms.


title: Ribosome

text: The first papers giving the structure of the ribosome at atomic resolution were published almost simultaneously in late 2000. The 50S (large prokaryotic) subunit was determined from the archaeon "Haloarcula marismortui" and the bacterium "Deinococcus radiodurans", and the structure of the 30S subunit was determined from "Thermus thermophilus". These structural studies were awarded the Nobel Prize in Chemistry in 2009. In May 2001 these coordinates were used to reconstruct the entire "T. thermophilus" 70S particle at 5.5 Å resolution.


title: Ribosome

text: Two papers were published in November 2005 with structures of the "Escherichia coli" 70S ribosome. The structures of a vacant ribosome were determined at 3.5 Å resolution using X-ray crystallography. Then, two weeks later, a structure based on cryo-electron microscopy was published, which depicts the ribosome at 11–15 Å resolution in the act of passing a newly synthesized protein strand into the protein-conducting channel.


title: Ribosome

text: The first atomic structures of the ribosome complexed with tRNA and mRNA molecules were solved by using X-ray crystallography by two groups independently, at 2.8 Å and at 3.7 Å. These structures allow one to see the details of interactions of the "Thermus thermophilus" ribosome with mRNA and with tRNAs bound at classical ribosomal sites. Interactions of the ribosome with long mRNAs containing Shine-Dalgarno sequences were visualized soon after that at 4.5–5.5 Å resolution.


title: Ribosome

text: In 2011, the first complete atomic structure of the eukaryotic 80S ribosome from the yeast "Saccharomyces cerevisiae" was obtained by crystallography. The model reveals the architecture of eukaryote-specific elements and their interaction with the universally conserved core. At the same time, the complete model of a eukaryotic 40S ribosomal structure in "Tetrahymena thermophila" was published and described the structure of the 40S subunit, as well as much about the 40S subunit's interaction with eIF1 during translation initiation. Similarly, the eukaryotic 60S subunit structure was also determined from "Tetrahymena thermophila" in complex with eIF6.


title: Ribosome

text: Ribosomes are minute particles consisting of RNA and associated proteins that function to synthesize proteins. Proteins are needed for many cellular functions such as repairing damage or directing chemical processes. Ribosomes can be found floating within the cytoplasm or attached to the endoplasmic reticulum. Their main function is to convert genetic code into an amino acid sequence and to build protein polymers from amino acid monomers.


title: Ribosome

text: Ribosomes act as catalysts in two extremely important biological processes called peptidyl transfer and peptidyl hydrolysis. The "PT center is responsible for producing protein bonds during protein elongation".


title: Ribosome

text: In summary, ribosomes have two main functions: Decoding the message, and the formation of peptide bonds. These two functions reside in the ribosomal subunits. Each subunit is made of one or more rRNAs and many r-proteins. The small subunit (30S in bacteria and archaea, 40S in eukaryotes) has the decoding function, whereas the large subunit (50S in bacteria and archaea, 60S in eukaryotes) catalyzes the formation of peptide bonds, referred to as the peptidyl-transferase activity. The bacterial (and archaeal) small subunit contains the 16S rRNA and 21 r-proteins ("Escherichia coli"), whereas the eukaryotic small subunit contains the 18S rRNA and 32 r-proteins (Saccharomyces cerevisiae; although the numbers vary between species). The bacterial large subunit contains the 5S and 23S rRNAs and 34 r-proteins ("E. coli"), with the eukaryotic large subunit containing the 5S, 5.8S, and 25S / 28S rRNAs and 46 r-proteins ("S. cerevisiae"; again, the exact numbers vary between species).


title: Ribosome

text: Ribosomes are the workplaces of protein biosynthesis, the process of translating mRNA into protein. The mRNA comprises a series of codons which are decoded by the ribosome so as to make the protein. Using the mRNA as a template, the ribosome traverses each codon (3 nucleotides) of the mRNA, pairing it with the appropriate amino acid provided by an aminoacyl-tRNA. Aminoacyl-tRNA contains a complementary anticodon on one end and the appropriate amino acid on the other. For fast and accurate recognition of the appropriate tRNA, the ribosome utilizes large conformational changes (conformational proofreading). The small ribosomal subunit, typically bound to an aminoacyl-tRNA containing the first amino acid methionine, binds to an AUG codon on the mRNA and recruits the large ribosomal subunit. The ribosome contains three RNA binding sites, designated A, P, and E. The A-site binds an aminoacyl-tRNA or termination release factors; the P-site binds a peptidyl-tRNA (a tRNA bound to the poly-peptide chain); and the E-site (exit) binds a free tRNA. Protein synthesis begins at a start codon AUG near the 5' end of the mRNA. mRNA binds to the P site of the ribosome first. The ribosome recognizes the start codon by using the Shine-Dalgarno sequence of the mRNA in prokaryotes and Kozak box in eukaryotes.


title: Ribosome

text: Although catalysis of the peptide bond involves the C2 hydroxyl of RNA's P-site adenosine in a proton shuttle mechanism, other steps in protein synthesis (such as translocation) are caused by changes in protein conformations. Since their catalytic core is made of RNA, ribosomes are classified as "ribozymes," and it is thought that they might be remnants of the RNA world.


title: Ribosome

text: In Figure 5, both ribosomal subunits (small and large) assemble at the start codon (towards the 5' end of the mRNA). The ribosome uses tRNA that matches the current codon (triplet) on the mRNA to append an amino acid to the polypeptide chain. This is done for each triplet on the mRNA, while the ribosome moves towards the 3' end of the mRNA. Usually in bacterial cells, several ribosomes are working parallel on a single mRNA, forming what is called a "polyribosome" or "polysome".


title: Ribosome

text: The ribosome is known to actively participate in the protein folding. The structures obtained in this way are usually identical to the ones obtained during protein chemical refolding; however, the pathways leading to the final product may be different. In some cases, the ribosome is crucial in obtaining the functional protein form. For example, one of the possible mechanisms of folding of the deeply knotted proteins relies on the ribosome pushing the chain through the attached loop.


title: Ribosome

text: Presence of a ribosome quality control protein Rqc2 is associated with mRNA-independent protein elongation. This elongation is a result of ribosomal addition (via tRNAs brought by Rqc2) of CAT tails": ribosomes extend the C-terminus of a stalled protein with random, translation-independent sequences of alanines and t"hreonines.


title: Ribosome

text: Free and membrane-bound ribosomes differ only in their spatial distribution; they are identical in structure. Whether the ribosome exists in a free or membrane-bound state depends on the presence of an ER-targeting signal sequence on the protein being synthesized, so an individual ribosome might be membrane-bound when it is making one protein, but free in the cytosol when it makes another protein.


title: Ribosome

text: Ribosomes are sometimes referred to as organelles, but the use of the term "organelle" is often restricted to describing sub-cellular components that include a phospholipid membrane, which ribosomes, being entirely particulate, do not. For this reason, ribosomes may sometimes be described as "non-membranous organelles".


title: Ribosome

text: Free ribosomes can move about anywhere in the cytosol, but are excluded from the cell nucleus and other organelles. Proteins that are formed from free ribosomes are released into the cytosol and used within the cell. Since the cytosol contains high concentrations of glutathione and is, therefore, a reducing environment, proteins containing disulfide bonds, which are formed from oxidized cysteine residues, cannot be produced within it.


title: Ribosome

text: When a ribosome begins to synthesize proteins that are needed in some organelles, the ribosome making this protein can become "membrane-bound". In eukaryotic cells this happens in a region of the endoplasmic reticulum (ER) called the "rough ER". The newly produced polypeptide chains are inserted directly into the ER by the ribosome undertaking vectorial synthesis and are then transported to their destinations, through the secretory pathway. Bound ribosomes usually produce proteins that are used within the plasma membrane or are expelled from the cell via "exocytosis".


title: Ribosome

text: In bacterial cells, ribosomes are synthesized in the cytoplasm through the transcription of multiple ribosome gene operons. In eukaryotes, the process takes place both in the cell cytoplasm and in the nucleolus, which is a region within the cell nucleus. The assembly process involves the coordinated function of over 200 proteins in the synthesis and processing of the four rRNAs, as well as assembly of those rRNAs with the ribosomal proteins.


title: Ribosome

text: The ribosome may have first originated in an RNA world, appearing as a self-replicating complex that only later evolved the ability to synthesize proteins when amino acids began to appear. Studies suggest that ancient ribosomes constructed solely of rRNA could have developed the ability to synthesize peptide bonds. In addition, evidence strongly points to ancient ribosomes as self-replicating complexes, where the rRNA in the ribosomes had informational, structural, and catalytic purposes because it could have coded for tRNAs and proteins needed for ribosomal self-replication. Hypothetical cellular organisms with self-replicating RNA but without DNA are called ribocytes (or ribocells).


title: Ribosome

text: As amino acids gradually appeared in the RNA world under prebiotic conditions, their interactions with catalytic RNA would increase both the range and efficiency of function of catalytic RNA molecules. Thus, the driving force for the evolution of the ribosome from an ancient self-replicating machine into its current form as a translational machine may have been the selective pressure to incorporate proteins into the ribosome's self-replicating mechanisms, so as to increase its capacity for self-replication.


title: Ribosome

text: Ribosomes are compositionally heterogeneous between species and even within the same cell, as evidenced by the existence of cytoplasmic and mitochondria ribosomes within the same eukaryotic cells. Certain researchers have suggested that heterogeneity in the composition of ribosomal proteins in mammals is important for gene regulation, "i.e.", the specialized ribosome hypothesis. However, this hypothesis is controversial and the topic of ongoing research.


title: Ribosome

text: Heterogeneity in ribosome composition was first proposed to be involved in translational control of protein synthesis by Vince Mauro and Gerald Edelman. They proposed the ribosome filter hypothesis to explain the regulatory functions of ribosomes. Evidence has suggested that specialized ribosomes specific to different cell populations may affect how genes are translated. Some ribosomal proteins exchange from the assembled complex with cytosolic copies suggesting that the structure of the "in vivo" ribosome can be modified without synthesizing an entire new ribosome.


title: Ribosome

text: Certain ribosomal proteins are absolutely critical for cellular life while others are not. In budding yeast, 14/78 ribosomal proteins are non-essential for growth, while in humans this depends on the cell of study. Other forms of heterogeneity include post-translational modifications to ribosomal proteins such as acetylation, methylation, and phosphorylation. "Arabidopsis", Viral internal ribosome entry sites (IRESs) may mediate translations by compositionally distinct ribosomes. For example, 40S ribosomal units without eS25 in yeast and mammalian cells are unable to recruit the CrPV IGR IRES.


title: Ribosome

text: Heterogeneity of ribosomal RNA modifications plays a significant role in structural maintenance and/or function and most mRNA modifications are found in highly conserved regions. The most common rRNA modifications are pseudouridylation and 2’-O methylation of ribose.


title: VfB Stuttgart

text: Verein für Bewegungsspiele Stuttgart 1893 e. V., commonly known as VfB Stuttgart (), is a German sports club based in Stuttgart, Baden-Württemberg. The club's football team is currently part of Germany's first division, the Bundesliga. VfB Stuttgart has won the national championship five times, most recently in 2006–07, the DFB-Pokal three times and the UEFA Intertoto Cup a record three times.


title: VfB Stuttgart

text: The football team plays its home games at the Mercedes-Benz Arena, in the Neckarpark which is located near the Cannstatter Wasen, where the city's fall beer festival takes place. Second team side VfB Stuttgart II currently plays in the Regionalliga Südwest, which is the second highest division allowed for a reserve team. The club's junior teams have won the national U19 championships a record ten times and the Under 17 Bundesliga six times.


title: VfB Stuttgart

text: A membership-based club with over 72,000 members, VfB is the largest sports club in Baden-Württemberg and the eighth-largest football club in Germany. It has departments for fistball, field hockey, track and field, table tennis, and football referees, all of which compete only at the amateur level. The club also maintains a social department, the "VfB-Garde".


title: VfB Stuttgart

text: "Verein für Bewegungsspiele Stuttgart" was formed through a 2 April 1912 merger of predecessor sides "Stuttgarter FV" and "Kronen-Club Cannstatt" following a meeting in the Concordia hotel in Cannstatt. Each of these clubs was made up of school pupils with middle-class roots who learned new sports such as rugby union and football from English expatriates such as William Cail who introduced rugby in 1865.


title: VfB Stuttgart

text: "Stuttgarter Fußballverein" was founded at the Zum Becher hotel in Stuttgart on 9 September 1893. "FV" were initially a rugby club, playing games at Stöckach-Eisbahn before moving to Cannstatter Wasen in 1894. The rugby club established a football section in 1908. The team drew players primarily from local schools, under the direction of teacher Carl Kaufmann, and quickly achieved its first success; in 1909, they were runners-up to "FSV 1897 Hannover" in the national rugby final, losing 6–3. Rugby was soon replaced by association football within the club, as spectators found the game too complicated to follow.


title: VfB Stuttgart

text: In 1909, "FV" joined the Süddeutschen Fußballverband (South German Football Association), playing in the second tier B-Klasse. In their second season "FV" won a district final against future merger partner "Kronen-Klub Cannstatt" before being defeated by "FV Zuffenhausen" in the county championship that would have seen the side promoted. They eventually advanced to the senior Südkreis-Liga in 1912.


title: VfB Stuttgart

text: "Cannstatter Fußballklub" was formed as a rugby club in 1890 and also quickly established a football team. This club was dissolved after just a few years of play and the former membership re-organized themselves as "FC Krone Cannstatt" in 1897 to compete as a football-only side. The new team joined the Süddeutschen Fußballverband (SFV) as a second division club and won promotion in 1904. "Krone" possessed their own ground, which still exists today as the home of TSV Münster.


title: VfB Stuttgart

text: Following the 1912 merger of these two clubs, the combined side played at first in the Kreisliga Württemberg and then in the Bezirksliga Württemberg-Baden, earning a number of top three finishes and claiming a title there in 1927. The club also made several appearances in the final rounds of the SFV in the late 1920s and early 1930s.


title: VfB Stuttgart

text: In 1933, VfB moved to Neckar Stadium, the site of its current ground. German football was re-organized that same year under the Third Reich into sixteen top-flight divisions called Gauligen. Stuttgart played in the Gauliga Württemberg and enjoyed considerable success there, winning division titles in 1935, 1937, 1938, 1940, and 1943 before the Gauliga system collapsed part way through the 1944–45 season due to World War II. The club had an intense rivalry with Stuttgarter Kickers throughout this period.


title: VfB Stuttgart

text: VfB's Gauliga titles earned the team entry to the national playoff rounds, with their best result coming in 1935 when they advanced to the final where they lost 4–6 to defending champions Schalke 04, the dominant side of the era. After a third-place result at the national level in 1937, Stuttgart was not able to advance out of the preliminary rounds in subsequent appearances.


title: VfB Stuttgart

text: VfB continued to play first division football in the Oberliga Süd, capturing titles in 1946, 1952, and 1954. They made regular appearances in the German championship rounds, emerging as national champions in 1950 and 1952, finishing as runner-up in 1953, and winning two DFB-Pokal titles in 1954 and 1958. The team which won four titles in eight years was led by Robert Schlienz who had lost his left arm in a car crash. Despite these successes, no player from the Stuttgart squad had a place in the team that won the 1954 FIFA World Cup.


title: VfB Stuttgart

text: Due to disappointing results in international competition including the 1958 and 1962 FIFA World Cup, and in response to the growth of professionalism in the sport, the German Football Association (Deutscher Fußball Bund, or DFB) replaced the regional top flight competitions with a single nationwide professional league in 1963. Stuttgart's consistently solid play through the 1950s earned them a place among the 16 clubs that would make up the original Bundesliga. As an amateur organisation, and due to proverbial Swabian austerity, the club hesitated to spend money, and some players continued to work in an everyday job. Throughout the balance of the decade and until the mid-1970s, the club would generally earn mid-table results. One of the few stars of the time was Gilbert Gress from Strasbourg.


title: VfB Stuttgart

text: In 1973, the team qualified for the UEFA Cup for the first time and advanced to the semi-finals of the 1974 tournament where they were eliminated by eventual winners Feyenoord (1–2, 2–2).


title: VfB Stuttgart

text: VfB Stuttgart was in crisis in the mid-1970s, having missed new trends in football such as club sponsorship. Attempts to catch up with new levels of professionalism by spending money failed. Towards the end of the 1974–75 season, with the team in imminent danger of being relegated to Second Bundesliga, local politician Gerhard Mayer-Vorfelder was elected as new president. However, a draw in the final game of the season meant that VfB would be ranked 16th and lose its Bundesliga status. The first season in the second league, considered the worst in its history, ended with VfB being ranked 11th, having even lost a home game against local rival SSV Reutlingen in front of just 1,200 spectators.


title: VfB Stuttgart

text: With new coach Jürgen Sundermann and new talents like Karlheinz Förster and Hansi Müller, the team built around Ottmar Hitzfeld scored one hundred goals in 1976–77 and thus returned to the top-flight after just two seasons.


title: VfB Stuttgart

text: The young team was popular for offensive and high-scoring play, but suffered from lack of experience. At the end of 1977–78, VfB was ranked fourth, but the average attendance of over 53,000 set the league record until the 1990s. They made another UEFA Cup semi-final appearance in 1980 and delivered a number of top four finishes on their way to their first Bundesliga title – the club's third national title – in 1984, now under coach Helmut Benthaus.


title: VfB Stuttgart

text: In 1986, VfB lost the DFB-Pokal final 2–5 to Bayern Munich. In the 1989 UEFA Cup Final, with Jürgen Klinsmann in their ranks, they lost out to Napoli (1–2, 3–3), where Diego Maradona was playing at the time.


title: VfB Stuttgart

text: In 1991–92, Stuttgart clinched its fourth title, in one of the closest races in Bundesliga history, finishing ahead of Borussia Dortmund on goal difference. Internationally, they had been eliminated from UEFA Cup play that season (1991–92) after losing their second round match to Spanish side Osasuna (2–3). As national champions, the club qualified to play in the UEFA Champions League in 1992–93, but were eliminated in the first round by Leeds United after a tie-breaking third match in Barcelona which was required due to coach Christoph Daum having substituted a fourth non-German player in the tie's second leg.


title: VfB Stuttgart

text: VfB did not qualify for any European competition again until 1997, by way of their third German Cup win, with coach Joachim Löw. They enjoyed a measure of success on their return, advancing to the 1998 European Cup Winners' Cup final in Stockholm, where they lost to Chelsea in what was the penultimate year of the competition. Only one player of the "magic triangle", captain Krassimir Balakov, remained after Giovane Élber and Fredi Bobic left. Löw's contract was not renewed and he was replaced by Winfried Schäfer, who in turn was sacked after one season.


title: VfB Stuttgart

text: Stuttgart's performance, however, fell off after this as the club earned just mid-table results over the next two seasons despite spending money on the transfer market and having veterans like Balakov.


title: VfB Stuttgart

text: Due to high debts and the lack of results, Gerhard Mayer-Vorfelder finally resigned from VfB in 2000 to take over offices at the DFB, UEFA, and FIFA. New president Manfred Haas had to renegotiate expensive contracts with players who seldom appeared on the field anyway. As in 1976, when Mayer-Vorfelder had taken over, the team had to be rebuilt by relying on talents from the youth teams. The VfB has Germany's most successful program in the German youth Championship.


title: VfB Stuttgart

text: Coach Ralf Rangnick had started a restructuring of the team that won the Intertoto Cup, but the resulting extra strain of the UEFA Cup participation ended in narrowly escaping from relegation in 2001 by clinching the 15th spot in the league table. Rangnick was replaced by Felix Magath.


title: VfB Stuttgart

text: With players like Andreas Hinkel, Kevin Kurányi, Timo Hildebrand, and Alexander Hleb earning themselves the nickname "the young and wild" , the club soon re-bounded and finished as Bundesliga runners-up in the 2002–03 season. In July 2003, Erwin Staudt became the new president of the club.


title: VfB Stuttgart

text: VfB qualified for their second Champions League appearance for 2003–04, beating Manchester United and Rangers once and Panathinaikos twice to advance from the group stage as runners-up to Manchester United. They were then matched against Chelsea in the round of 16, falling 0–1 and 0–0 over two legs.


title: VfB Stuttgart

text: Stuttgart continued to play as one of the top teams in the country, earning fourth and fifth place Bundesliga finishes in 2003–04 and 2004–05 respectively, and again taking part in the UEFA Cup, but without great success. In addition, coach Magath and several players left for another clubs: Kevin Kurányi for Schalke 04, Philipp Lahm for Bayern Munich and Alexander Hleb for Arsenal.


title: VfB Stuttgart

text: Halfway through the disappointing 2005–06 season, Giovanni Trapattoni was sacked and replaced by Armin Veh. The new coach was designated as a stop-gap due to having resigned from Hansa Rostock in 2003 to focus on his family and having no football job since 2004, save for coaching his home team FC Augsburg for one season. Supported by new manager Horst Heldt, Veh could establish himself and his concept of focusing on promising inexpensive players rather than established stars. Team captain, Zvonimir Soldo, retired, and other veterans left the team that slipped to ninth place and did not qualify for European competition for the first time in four years.


title: VfB Stuttgart

text: Despite early-season losses and ensuing criticism in 2006–07, including a 3–0 loss at home to 1. FC Nürnberg, Veh managed to turn the collection of new players like Mexicans Pável Pardo, and Ricardo Osorio, Brazilian Antônio da Silva and fresh local talents, including Mario Gómez, Serdar Tasci, and Sami Khedira, into a strong contender that led the league on 12 November 2006 for the first time in two years. Stuttgart established themselves among the top five and delivered a strong challenge for the Bundesliga title by winning their final eight games. In the penultimate week on 12 May 2007, Stuttgart beat VfL Bochum 3–2 away from home, taking the Bundesliga lead from Schalke 04 and at minimum securing a spot in the 2007–08 Champions League. After trailing 0–1 in the final match of the season against Energie Cottbus, Stuttgart came back to win 2–1 and claim their first Bundesliga title in 15 years. The victory celebrations in Stuttgart, totalling 250,000 people, even topped those of Germany's third place win over Portugal in the 2006 FIFA World Cup.


title: VfB Stuttgart

text: In addition, VfB had their first ever chance to win the double as they also reached the final of the German Cup for the first time since their victory there ten years former. Their opponents in the cup final in Berlin were 1. FC Nürnberg, a team that had beaten them twice by three goals in regular season, 3–0 and 4–1, and had last won the cup in 1962. With the game level at 1–1 in the first half, Stuttgart's scorer Cacau was sent off. Nürnberg gained a 2–1 lead early in the second half, but the ten men of VfB managed to fight back and equalize. In the second half of extra time, however, with both teams suffering from exhaustion and the humid conditions, Nürnberg scored the winning goal.


title: VfB Stuttgart

text: The 2007–08 UEFA Champions League draw on 30 August 2007 paired the German champions with Spanish giants Barcelona, French champions Lyon and Scottish Old Firm side Rangers. Like in the 2003–04 UEFA Champions League season, Stuttgart's 2007–08 European campaign started with a match at Ibrox Park in Glasgow against Rangers. It ended in a 2–1 defeat. The second match at home against Barcelona was likewise lost, 0–2, as well as the third match, against Lyon at home, with the visitors coming out 2–0 winners from two-second-half strikes. Five defeats and just one win (over Rangers) meant the early exit on the European stage. In the league, they managed to finish in sixth place after a poor start. New German international star Mario Gómez scored 19 goals.


title: VfB Stuttgart

text: Subsequently, UEFA Cup qualification was ensured in the summer by succeeding in the 2008 UEFA Intertoto Cup.


title: VfB Stuttgart

text: The 2008–09 season, like the one before it, got off to a bad start. After matchday 14 in November, VfB was only 11th in the table and as a result, Armin Veh was sacked and replaced by Markus Babbel. After exiting the German Cup after a 1–5 thrashing from Bayern Munich in January, prospects improved considerably and the team ended third in the table, with second place just being missed after a loss to Bayern on the last matchday. That meant the chance of making the Champions League again.


title: VfB Stuttgart

text: Internationally, VfB mastered the group stages of the 2008–09 UEFA Cup, but lost to Cup defenders Zenit Saint Petersburg in the round of the last 32 in February.


title: VfB Stuttgart

text: Stuttgart went into the 2009–10 season with Mario Gómez leaving for Bayern Munich, just as Pavel Pogrebnyak arrived from Zenit Saint Petersburg and Alexander Hleb returning on loan from Barcelona.


title: VfB Stuttgart

text: On the European level, Stuttgart started the season with a huge success by qualifying for the group stage of the 2009–10 UEFA Champions League. Stuttgart entered that competition for the third time in six years (after 2003 and 2007) by defeating Romanian side Politehnica Timișoara in the Champions League play-off round on 18 and 26 August 2009. VfB were then drawn into Group G against Spanish side Sevilla, Scottish champions Rangers, against whom they had also been drawn against in their previous two Champions League Group stage appearances, and Romanian champions Unirea Urziceni. With two wins (one each against Rangers and Unirea), three draws (one each against all opponents) and a loss (to Sevilla) they managed second spot in the group, thus qualifying for the round of the last 16, where they had to face title holders Barcelona in late winter. After a superb home game against Barça which Stuttgart, however, did not manage to win (1–1), they were eliminated in a 4–0 rout at Camp Nou.


title: VfB Stuttgart

text: In the 2009–10 DFB-Pokal, they did not proceed further than the last 16 either, losing to second-tier side SpVgg Greuther Fürth. That defeat came in the course of a disappointing first half of the 2009–10 Bundesliga. As a consequence of slipping to 16th spot in December, young coach Markus Babbel was fired after matchday 15 and replaced by the more experienced Swiss Christian Gross. Under his tenure, VfB improved their situation domestically as well as internationally before the winter break. During that break, Thomas Hitzlsperger, Jan Šimák and Ludovic Magnin left the club; Cristian Molinaro was loaned out from Juventus. In the later half of the season, the team – as in the 2008–09 season – had a fantastic, almost unbroken, winning streak. As the best team of that second (return) round of the Bundesliga, the Swabians under Gross climbed into the upper half of the table and, after a sensational rally, eventually managed to secure European football for the following season by qualifying for the Europa League.


title: VfB Stuttgart

text: The 2010–11 season was a mediocre one—after again spending the first half of the season almost always in the relegation zone (17th and 18th spot), with Christian Gross being fired and interim coach Jens Keller taking over for the rest of the first leg, Bruno Labbadia was hired as new coach in January and managed to save VfB from relegation. Eventually, the team finished 12th after a decent second-half performance. In July 2011, Erwin Staudt did not participate again in the election of the president and Gerd E. Mäuser was elected as president.


title: VfB Stuttgart

text: In the following 2011–12 season, they managed to constantly climb up the table; this was especially thanks to a long unbeaten streak in the spring. Subsequently, VfB qualified for the 2012–13 UEFA Europa League. Key players during that season were Martin Harnik, who scored 17 goals, as well as winger Gōtoku Sakai and forward Vedad Ibišević, who both came to Stuttgart in January 2012.


title: VfB Stuttgart

text: With effect from 3 June 2013, Gerd E. Mäuser announced his resignation as president of VfB Stuttgart. On 2 July 2013, the supervisory board of the club named Bernd Wahler as the candidate for the presidential elections. On 22 July 2013, Wahler was elected by 97.4% of the votes cast.


title: VfB Stuttgart

text: After barely avoiding relegation from the Bundesliga in the 2014–15 season, Stuttgart were relegated to the 2. Bundesliga in the 2015–16 season after finishing in 17th place, having been unable to lift themselves out of the bottom three positions until the end of the season. Following matchday 13, a home match against FC Augsburg and their second consecutive 4–0 loss, Stuttgart decided to terminate Alexander Zorniger's contract and appointed Jürgen Kramny as their manager for an indefinite period. After Stuttgart were relegated to the 2. Bundesliga, Wahler resigned as president on 15 May 2016. Kramny was subsequently sacked as coach.


title: VfB Stuttgart

text: On 17 May 2016, Jos Luhukay was announced as the new head coach. Luhukay resigned on 15 September 2016 and was replaced by Hannes Wolf. At the end of the season, Stuttgart returned to the Bundesliga as the 2. Bundesliga champions. On 22 December 2017, after nearly 10 years since his departure, Bundesliga title winning striker Mario Gomez returned to the team from fellow Bundesliga side VfL Wolfsburg, The team made a solid return season to the Bundesliga, finishing in 7th place. However, they slumped to 16th the following season, eventually ending up relegated via play-offs against Union Berlin.


title: VfB Stuttgart

text: Stuttgart appointed Thomas Hitzlsperger as the sporting CEO, and in April they appointed Sven Mislintat as the sporting director, coming from Borussia Dortmund and Arsenal. In July 2019, Stuttgart was relegated to the second division, and started to rebuild the team. In mid-season, December 2019, former coach Tim Walter was fired and Pellegrino Matarazzo was signed. After one season, Stuttgart returned to the Bundesliga after finishing second in the 2019–20 2. Bundesliga season. In 2020, the contract of Mislintat was prolonged to give him more responsibility.


title: VfB Stuttgart

text: Stuttgart stayed in the Bundesliga in the 2020–21 season, finishing in ninth place in the league.<ref name="Bundesliga Tabelle 2020/21"></ref> In the 2021–22 season, the team narrowly avoided relegation; a win against 1. FC Köln on the last match day guaranteed them a spot in the first league for a third consecutive season.


title: VfB Stuttgart

text: The home ground of VfB Stuttgart is the Mercedes-Benz Arena which was originally built in 1933. It lies close to the River Neckar on Bad Cannstatt's Mercedes-Straße near the new Mercedes-Benz Museum and Mercedes-Benz factory. After being renovated several times, the stadium was able to hold a maximum capacity of 55,896 spectators (50,000 for international matches). For the 1974 FIFA World Cup, the Gottlieb-Daimler-Stadion (its original name) was one of the venues for the 2006 FIFA World Cup, hosting five preliminary round matches, a first knockout round match (England vs. Ecuador) and the third place play-off (Germany vs. Portugal). From the 2008–09 season, the stadium was named the Mercedes-Benz-Arena, starting with a pre-season friendly against Arsenal on 30 July 2008. The stadium recently went through extensive restructuring and rebuilding as it was being converted into a pure football arena. In 2011, the capacity was increased to 60,449.


title: VfB Stuttgart

text: The longest rivalry of VfB is the city rivalry with Stuttgarter Kickers ("Die Roten"/"Reds" against "Die Blauen"/"Blues"). However, the respective first teams of the two clubs haven't played each other since Kickers were relegated to the 2. Bundesliga in 1992. Thus, this derby has increasingly been overtaken in importance by the Baden-Württemberg-Derby between VfB and Karlsruher SC. In this derby, old Badenese-Württembergian animosities are played out. The rivalry with Bavarian side Bayern Munich ("Süd-/South Derby") is mainly one-sided, as VfB fans are angry at Bayern for buying some of Stuttgart's best players and coaches in recent years, such as Giovane Élber, Felix Magath, Mario Gómez, and Benjamin Pavard.


title: VfB Stuttgart

text: Regional friendships exist between VfB and the South Württemberg side SSV Reutlingen 05 (the "little brother" of VfB) as well as with North Württembergers SpVgg Ludwigsburg. On a national level, supporters groups of VfB used to be closely connected with those of Energie Cottbus, 1. FC Saarbrücken, Bayer Leverkusen and Eintracht Frankfurt. All of these supporter group friendships have been discontinued by today or are only maintained by few supporter groups. Current ultras friendships are with the ultras of SSV Reutlingen 05 and Italian club Cesena.


title: VfB Stuttgart

text: In 2005, a cooperation treaty between VfB and Swiss Super League side St. Gallen was signed, with particular emphasis on the youth sectors of both clubs.


title: AgustaWestland AW101

text: The AgustaWestland AW101 is a medium-lift helicopter in military and civil use. First flown in 1987, it was developed by a joint venture between Westland Helicopters in the United Kingdom and Agusta in Italy in response to national requirements for a modern naval utility helicopter. Several operators, including the armed forces of Britain, Denmark, and Portugal, use the name Merlin for their AW101 aircraft. It is manufactured at factories in Yeovil, England, and Vergiate, Italy. Licensed assembly work has also taken place in Japan and the United States.


title: AgustaWestland AW101

text: Prior to 2007, the aircraft had been marketed under the designation EH101. The original designation was EHI 01, from the name given to the Anglo-Italian joint venture—European Helicopter Industries—but a transcription error changed this to EH101. In 2000, Westland Helicopters and Agusta merged to form AgustaWestland, leading to the type's current designation.


title: AgustaWestland AW101

text: The AW101 entered into service in 1999 and has since replaced several older helicopter types, such as the Sikorsky SH-3 Sea King, performing roles such as medium-sized transport, anti-submarine warfare, search and rescue, and ship-based utility operations. The Royal Canadian Air Force (RCAF) operates the CH-149 Cormorant variant for air-sea rescue. Another variant, the Lockheed Martin VH-71 Kestrel, was produced to serve in the United States presidential transport fleet before the program was cancelled and the aircraft sold off to Canada for parts. Civil operators use the AW101 for passenger and VIP transportation. The type has been deployed to active combat theatres, such as in support of coalition forces during the Iraq War and the War in Afghanistan.


title: AgustaWestland AW101

text: In 1977, the UK Ministry of Defence issued a requirement for an anti-submarine warfare (ASW) helicopter to replace the Royal Navy's Westland Sea Kings, which were becoming inadequate in the face of advances in Soviet submarine technology. Westland Helicopters put together a proposal, designated WG.34, for a three-engined helicopter of similar dimensions to the Sea King; the WG.34 was to feature more autonomy and a greater range than its predecessor. At the same time, the Italian Navy ("Marina Militare") was also considering the replacement of its fleet of Sea Kings, which had been built by the Italian company Agusta; Westland and Agusta soon began talks regarding the joint development of a successor helicopter.


title: AgustaWestland AW101

text: Agusta and Westland finalised an agreement to work on the project together, and formed a jointly owned new company, EH Industries Limited (EHI), to pursue the development and marketing of the new helicopter to potential operators. On 12 June 1981, the UK government confirmed its participation in the project, allocated an initial budget of £20 million to develop nine pre-series examples. A major agreement, which secured funding for the majority of the EH101's development program, was signed by both the British and Italian governments in 1984. At the 1985 Paris Air Show, Agusta showed a mock-up of a utility version of the new helicopter, leading to a more generalised design that could be customised to meet the needs of various civilian or military customers. The first prototype flew on 9 October 1987.


title: AgustaWestland AW101

text: In 1987, Canada selected the EH101 to replace their Sea Kings in the anti-submarine warfare and search and rescue roles. The EH101's third engine and increased range compared favorably with rival aircraft, such as the Sikorsky Seahawk. The range and de-icing capability were also seen as vital for North Atlantic operations. The fledgling EH101, of which up to 50 were on order to replace the Canadian Armed Forces's (CAF) Sea Kings, found itself subject to a wider political battle between the Conservative and Liberal parties, the latter viewing the aircraft as too costly. Critics attacked the EH101 purchase as excessive and unnecessary after the Cold War's end in the early 1990s. Wide-ranging cost estimates were presented by both proponents and opponents of the EH101 procurement, with opponents backing life extensions of Sikorsky CH-124 Sea King and Boeing Vertol CH-113 Labrador helicopter fleets. The EH101 controversy was seen as a factor in the 1993 Canadian federal election. The order was cancelled by the new Liberal government in 1993 resulting in a $470 million cancellation fee.


title: AgustaWestland AW101

text: Several pre-production aircraft were assembled during the late 1980s and early 1990s. The first pre-production aircraft had its first flight powered by General Electric CT7-2A engines on 9 October 1987. Flight tests were suspended for six months following the crash of the second pre-production aircraft on 21 January 1993. On 6 June 1993, the first EH101 took its maiden flight with the Rolls-Royce Turbomeca RTM322 turboshaft engine. Nine prototypes were built to explore military and civil applications, including a "heliliner" configuration. In February 1995, Britain formally placed its first order for a total of 22 EH101s; this was quickly followed by Italy's order for 16 EH101s in October 1995. The EH101 order was not without controversy, the RAF had declared its preference for an all-Chinook fleet; also, Boeing allegedly offered cheaper terms for the Chinook. RAF deliveries began in 1997; RN deliveries started the following year.


title: AgustaWestland AW101

text: Following the merger of Westland and Agusta to form AgustaWestland in 2000, there was no need for the separate EHI entity; the EH101 was formally re-branded as the AW101 in 2007. By April 2009, more than 180 AW101s had been sold worldwide; the combined operational fleet had also accumulated a total of 170,000 flying hours.


title: AgustaWestland AW101

text: In November 2007, Algeria signed a contract for 6 AW101 helicopters. In August 2012, it was reported that Algeria had signed an agreement with AgustaWestland for the provision of up to 80 helicopters, 42 of which were to be AW101s. Under the terms of this arrangement, early aircraft were to be manufactured by AgustaWestland, while Algeria was to commence the assembly of some AW101s later on.


title: AgustaWestland AW101

text: By September 2013, AgustaWestland was in the process of acquiring civil certification for the AW101, prospective customers include offshore oil platform operators and VIP clients. As of February 2014, AgustaWestland was considering adapting the AW101 as a heavyweight unmanned aerial vehicle, it is proposed that in this configuration an AW101 could be optionally manned.


title: AgustaWestland AW101

text: On 7 June 2010, it was announced that Boeing had acquired a manufacturing license and the rights from AgustaWestland for US production of a localised AW101 variant, designated as the Boeing 101. In October 2012, the AW101 was submitted in a U.S. Air Force competition to replace the HH-60 Pave Hawk; however, the bid was dropped three months later.


title: AgustaWestland AW101

text: The AW101 Merlin follows a conventional design layout, but makes use of advanced technologies, such as the design of the rotor blades, avionics systems, and extensive use of composite materials. The fuselage structure is modular and comprises an aluminium–lithium alloy, designed to be both light and damage-resistant. The AW101 is designed for operating in extreme weather conditions; it is fitted with a de-icing system and rated to operate in temperatures ranging between −45 and +50 °C. The aircraft's control systems allow the AW101 to maintain a stable hover in crosswinds.


title: AgustaWestland AW101

text: An active vibration control system, known as the "active control of structural response system", reduces airframe vibration by up to 80%, increasing crew comfort and minimising buildup of stress on the airframe. The cockpit is fitted with armoured seats for the crew, and can withstand an impact velocity of over 10 m/s. Dual flight controls are provided, though the AW101 can be flown by a single person. The pilots' instrument displays include six full-colour high-definition screens and an optional mission display; a digital map or forward looking infrared (FLIR) display can also be installed.


title: AgustaWestland AW101

text: The AW101 is powered by three turboshaft engines. Initially the Rolls-Royce Turbomeca RTM322 producing and the General Electric CT7 producing were the two available engine types, but by 2020 new aircraft were only being sold with the CT7-8E. The RTM322 powerplant was specifically developed for the AW101; it was subsequently adopted on the AgustaWestland WAH-64 Apache and the NHIndustries NH90 helicopters. According to Rolls-Royce, about 80% of AW101s use the RTM322


title: AgustaWestland AW101

text: The engines power an diameter five-bladed main rotor. The rotor blades are constructed from carbon/glass with nomex honeycomb and rohacell foam, edged with titanium alloy in a sandwich construction. The shaping of the main rotor blades is derived from the BERP rotor blades first used on the Westland Lynx. This blade design improves aerodynamic efficiency at the blade tip and reduces the acoustic signature. Improved BERP IV rotors have since been developed; when installed this increases the AW101's maximum takeoff weight.


title: AgustaWestland AW101

text: Each engine is supplied by a separate fuel tank using dual booster pumps. Optional fourth and fifth tanks can be added to act as a reservoir supply, topping up the main tanks during flight, increasing range or endurance. The AW101 can also be fitted with a probe for aerial refuelling. Self-sealing fuel tanks are an optional item to be selected by the customer. An inlet particle separator system can be installed, protecting the engine when operating in sandy environments.


title: AgustaWestland AW101

text: Most variants of the AW101 are equipped with self-defence systems, such as chaff and flare dispensers, directed infrared countermeasures (infrared jammers), ESM (electronic support measures in the form of RF heads), and a laser detection and warning system. British Merlins have been outfitted with protective armour against small-arms fire. A side-mounted forward looking infrared (FLIR) imaging sensor has been fitted to some variants.


title: AgustaWestland AW101

text: Two hardpoints are present in the underside of the airframe on which the HM1 model can carry four Sting Ray torpedoes or Mk 11 Mod 3 depth charges. Some customers have chosen to deploy the Marte anti-ship missile on the AW101; as of 2011, the Royal Navy is considering equipping their Merlin fleet with an anti-surface missile. The Mk1, Mk3 and Mk3A variants can mount general purpose machine guns in up to five locations in the main cabin, aimed out of both door and window apertures. AgustaWestland has examined the integration of rockets and additional ground-attack weapons.


title: AgustaWestland AW101

text: Westland and IBM formed a consortium in 1991 to perform the helicopter's complex systems integration. The AW101 features a network of helicopter management and mission systems designed to reduce pilot workload and enable the helicopter to undertake a wide variety of missions. A digital automatic flight control system (AFCS) is employed by the AW101. The AFCS allows the operation of a four-axis (pitch, roll, yaw and collective) autopilot and the automatic stabilisation system, and is linked in with the aircraft's flight management systems. The AFCS, manufactured by Smiths Aerospace, is a dual-duplex system using two flight computers to provide redundancy and fault-tolerance.


title: AgustaWestland AW101

text: The AW101's navigation system includes a GPS receiver and inertial navigation system, VHF omnidirectional radio range (VOR), instrument landing system (ILS), TACAN, and automatic direction finding. The Mk1 and Mk3 are equipped with a Doppler velocity system (DVS) which provides relative ground velocities; the DVS is also linked into the AFCS as part of the autostabilisation system. For safety, the aircraft is equipped with obstacle and terrain avoidance warning systems, traffic collision avoidance system (TCAS), and both voice and flight data recorders.


title: AgustaWestland AW101

text: The AW101 is equipped with the Blue Kestrel search and detection radar which is capable of 360 degree scanning and can detect small targets as far as 25 nautical miles. As part of the Royal Navy's Merlin HM2 upgrade program, Lockheed Martin implemented a series of improvements to the radar, notably allowing it to track 40 times the number of targets previously capable. Danish EH101s are fitted with the RDR-1600 search and weather radar. Mk 2 Royal Navy Merlins are equipped with the AQS901 anti-submarine system for processing sonographic data from sonobuoys to detect and target submerged submarines. The AQS901 was derived from the system on the earlier Hawker Siddeley Nimrod maritime patrol aircraft.


title: AgustaWestland AW101

text: The AW101 is typically operated by a crew of three: a pilot, an observer, and a crewman/operator. The pilot is able to fly for the majority of a mission in a hands-off mode, enabled by the sophisticated autopilot. All crew members have individual access to management computers and tactical information.


title: AgustaWestland AW101

text: The fuselage has a volume of and the cargo compartment is in length, wide and high. The military version of the AW101 can accommodate up to 24 seated or 45 standing combat troops and their equipment. Alternative loads include a medical team and 16 stretchers, and cargo pallets.


title: AgustaWestland AW101

text: The ramp, , can take a load, allowing it to carry vehicles such as Land Rovers. The ramp and cabin floor are fitted with flush tie-down points. A cargo hook under the fuselage can carry external loads of via the use of a semi-automatic cargo release unit (SACRU). A rescue hoist and a hover trim controller are fitted at the cargo door. An optional cargo winch can be installed near to the rear ramp.


title: AgustaWestland AW101

text: The British Royal Navy's final order was for 44 ASW aircraft, originally designated "Merlin HAS.1" (Helicopter, Anti-Submarine Mark 1) but soon changed to "Merlin HM1" (Helicopter, Maritime Mark 1). The first fully operational Merlin was delivered on 17 May 1997, entering service on 2 June 2000. All aircraft were delivered by the end of 2002, and are operated by 3 Fleet Air Arm squadrons: 814 NAS, 820 NAS, 824 NAS and 829 NAS (now disbanded and merged with 814 NAS), all based at RNAS Culdrose in Cornwall. 700 NAS was the Merlin Operational Evaluation Unit from 2000 to 2008. In March 2004, Navy Merlins were temporarily grounded following an incident at RNAS Culdrose in which a tail rotor failed due to a manufacturing defect. An improved tail rotor was designed and adopted on most AW101s which significantly reduced associated maintenance.


title: AgustaWestland AW101

text: In 1995, it was announced that the Navy's Westland Lynx helicopters would be retired in favour of an all-Merlin fleet. However, the subsequent Strategic Defence and Security Review 2010 stated that the future naval helicopters would be the Merlin and the Wildcat, a derivative of the Lynx. Royal Navy Merlins have seen action in the Caribbean, on counter-narcotics and hurricane support duties, as well as maritime security duties in the Persian Gulf. Merlins have also seen active duty in Iraq, providing support to British and coalition forces based in the region.


title: AgustaWestland AW101

text: The Merlin HM1 has been cleared to operate from the Royal Navy's aircraft carriers, amphibious assault ships, Type 23 frigates, Type 45 destroyer and several Royal Fleet Auxiliary (RFA) vessels including the . 30 aircraft have been upgraded to "Merlin HM2" standard under the £750m Merlin Capability Sustainment Programme; Lockheed Martin UK delivered the final HM2 on 11 July 2016. The HM2 has a new mission system, digital cockpit, electro-optical camera and multi-static sonar processing. The HM2 achieved IOC on 30 June 2014 after flying 480 hours from "Illustrious" during Exercise Deep Blue earlier that month. It was also reported that some of the eight airframes not scheduled to be upgraded for financial reasons may be updated. Five HM2s are in maintenance at a time, leaving 25 available, of which 14 were theoretically to be assigned to the . However, in practice with just 30 Merlin HM2s in service, it may be impossible to deploy 14 aircraft on a single operational carrier on a full time basis. During the 2021 carrier strike group deployment to the Pacific, for instance, 7 Merlins were embarked with the task group.


title: AgustaWestland AW101

text: In addition to its ASW role, the HM2 will be able to carry an airborne early warning (AEW) pod known as the Crowsnest, replacing the Sea King ASaC7. In September 2011, Thales UK proposed re-using Sea King ASaC7 equipment, such as the Searchwater 2000, on the Merlin; Lockheed Martin has proposed developing a new multi-functional sensor for both the AW101 and other aircraft. Lockheed originally planned to use a derivative of the F-35's APG-81 radar; however, a rival Elta system and the Thales system both commenced flight trials in 2014. On 22 May 2015, the MOD and prime contractor Lockheed Martin UK selected Thales to provide the radar and mission system for the Crowsnest. Initial operating capability of the system was significantly delayed. While Crowsnest was deployed with the U.K. carrier strike group in 2021, it experienced operating challenges and revised plans will now see Crowsnest achieve initial operating capability in the second quarter of 2023 and full operating capability in 2024/25. It has been reported that initially only five Merlins will be equipped with Crowsnest, three of these being normally assigned to the "high readiness" aircraft carrier.


title: AgustaWestland AW101

text: On 15 December 2009, plans were announced to transfer RAF Merlin HC3s and HC3As to the Royal Navy's Commando Helicopter Force to replace retiring Sea King HC4 helicopters. The Sea King was set to retire in 2016, leaving the Navy operating a combination of the Wildcat and Merlin. 846 NAS reformed with ex-RAF Merlin HC3s on 30 September 2014; 845 NAS followed on 9 July 2015. On 25 May 2018, the first of 25 converted Royal Marines Commando Merlin Mk4/4A were delivered to Royal Naval Air Station (RNAS) Yeovilton. In July 2020, the Merlin HM2 and HC4/4A helicopters were planned to be in service until 2029 and 2030, respectively. On 11 June 2021, it was confirmed that their Out of Service Date (OSD) had been moved to 2040.


title: AgustaWestland AW101

text: The RAF ordered 22 Merlin HC3 for transport missions, the first of which entered service in January 2001 with No. 28 Squadron RAF based at RAF Benson. The type is equipped with extended-range fuel tanks and is capable of air-to-air refuelling. The Merlin is frequently utilised for troop transport duties and for the transport of bulky objects, either internally or underslung, including vehicles and artillery. The Merlin Depth Maintenance Facility at RNAS Culdrose performed most tasks upon the Merlin HC3.


title: AgustaWestland AW101

text: The Merlin's first operational deployment was to the Balkans region in 2003. RAF Merlins were first deployed to Iraq as part of Operation Telic in 2004, supporting coalition forces and were operated as the main medevac asset in southern Iraq; both Flight Lieutenant Kev Harris and Flight Lieutenant Michelle Goodman were awarded the DFC during this period. Merlins routinely operated around Basra until Britain's withdrawal in June 2009.


title: AgustaWestland AW101

text: In 2002, Westland made an unsuccessful unsolicited offer to the British Ministry of Defence, proposing an enhanced Merlin variant intended to satisfy the demand for additional lift capacity. An alternative measure was the acquisition of six AW101s from Denmark in 2007; designated "Merlin HC3A", these were assigned to the RAF, allowing Merlins to be deployed in Afghanistan. The HC3A is used for training and not for frontline operations due to various configuration differences. In December 2007, a second Merlin squadron, No. 78 Squadron was formed at RAF Benson.


title: AgustaWestland AW101

text: In 2009, five Merlin Mk3s were operating in Afghanistan, transporting troops and supplies. The deployment to Afghanistan was criticised as the aircraft reportedly lacked protective Kevlar armour. By July 2010, the Merlin fleet was fully fitted with ballistic armour. The deployment of Merlins to Afghanistan allowed the detachment of Sea Kings to be withdrawn from the region in October 2011. As part of the UK drawdown in Afghanistan, Merlins were withdrawn from theatre in June 2013.


title: AgustaWestland AW101

text: In 2012, the RAF's Merlin HC3/3A fleet began to be transferred to the Royal Navy for use by the Commando Helicopter Force. Royal Navy personnel worked alongside RAF crew at Benson to build experience during the transition. The £454m Merlin Life Sustainment Programme resulted in 25 HC3/3A airframes being fitted with the cockpit electronics of the HM2, folding tails and main rotor heads, strengthened landing gear, deck lashing mounting points, obsolescence updates, fast-roping points and a common emergency egress system. The first HC4 is to begin flight trials in September 2017, with an IOC in mid-2018; an interim folding main rotor head will be fitted to some HC3 for shipborne operations prior to the HC4 upgrade.


title: AgustaWestland AW101

text: Command of the UK Merlin HC3/3A fleet was formally transferred from the RAF to the Royal Navy during a ceremony at RAF Benson on 30 September 2014. As part of the same ceremony, the RAF's 78 Sqn was disbanded and the Royal Navy's 846 Naval Air Squadron stood-up with the Merlin. The RAF's 28(AC) continued to operate as part of the Commando Helicopter Force until July 2015, when 28(AC) Sqn stood down and 845 Naval Air Squadron stood-up. 846 NAS relocated from RAF Benson to RNAS Yeovilton in March 2015, with 845 NAS following in June 2016.


title: AgustaWestland AW101

text: In 1997, the Italian government ordered 16 AW101 helicopters for the Italian Navy, with options for four more. These AW101 included eight of the anti-surface/submarine (ASuW/ASW) version, four airborne early warning (AEW), four amphibious support helicopters (ASH). The government then exercised its option for four additional ASH helicopters, which were delivered by 2006. The same year the government ordered two more AW101 ASH helicopters in a slightly modified version.


title: AgustaWestland AW101

text: The first Italian Navy production helicopter ("MM81480") flew on 4 October 1999 and was officially presented to the press on 6 December 1999. Italy accepted delivery of the 21st AW101, configured for anti-submarine warfare, on 4 August 2009. In total 22 AW101 helicopters have been delivered to the Italian Navy.


title: AgustaWestland AW101

text: Italian AW101s have operated from a variety of ships and have seen service overseas; in 2009 the Italian Navy used its AW101 fleet as executive transports for visiting heads of state and officials during the 35th G8 summit. In 2010, the Italian Navy deployed three AW101s to Afghanistan, where they were flown in both the transport and utility roles. In 2011, it was reported that the Italian contingent in Afghanistan, consisting of AW101s, had been providing coverage of a wide area of the country.


title: AgustaWestland AW101

text: In June 2011 the AW101 was chosen by the Italian Air Force to replace its ageing Sea King HH-3F helicopters in the combat search and rescue role. A total of 15 helicopters in the HH-101A variant were ordered and delivered between 2016 and 2020.


title: AgustaWestland AW101

text: In 1997, in light of the declining condition of its helicopter fleet, Canada launched the Canadian Search and Rescue Helicopter competition. It was won by the EH101, which was designated "CH-149 Cormorant" in Canadian service.


title: AgustaWestland AW101

text: In 2004, the EH101 was entered into a Canadian competition to replace the shipboard Sea King fleet, but the Sikorsky CH-148 Cyclone was selected. In 2013, following difficulties with the CH-148 procurement, the Royal Canadian Air Force (RCAF) was reported to be seriously considering cancelling the contract with Sikorsky and was investigating the possibility of procuring the AW101 instead. However, an initial batch of six Cyclones was delivered to the RCAF in June 2015.


title: AgustaWestland AW101

text: In 2001, the Royal Danish Air Force (RDAF) announced the purchase of eight EH101s for SAR duties and six tactical troop transports for 722 Squadron. The last of the 14 AW101s was delivered in March 2007 and the first SAR AW101s became operational out of Karup Airport in April 2007. In 2007, the six troop transport AW101s were transferred to the British MOD; in exchange, the British government ordered six new-build AW101s as replacements for the RDAF.


title: AgustaWestland AW101

text: Danish AW101s have a higher gross weight capacity of 15,600 kg and were, as delivered, coated in a paint designed to reduce the aircraft's infrared signature. In the SAR role, RDAF AW101s have a crew of six and were initially painted yellow to distinguish themselves from AW101 allocated to military duties, but were later painted green, and all 14 AW101s are used for SAR and troop transport.


title: AgustaWestland AW101

text: On 28 January 2008, the drive shaft of a Danish AW101 broke, leading to an emergency landing at Billund Airport. Following the incident, the Danish fleet was grounded as a precaution and the AW101's future was publicly debated. In the first six months of 2008, the RDAF reported an operational availability of roughly 50%, well below the target of 80%, partly due to an inadequate maintenance organisation and staff shortages.


title: AgustaWestland AW101

text: In January 2011, the Danish Ministry of Defence reportedly could not afford the retrofitting of the AW101 fleet for Afghanistan operations, against earlier reports of a deployment in 2012. In February 2013, Aviation Week reported that earlier reliability problems had been resolved and that a full upgrade package would be applied to Danish AW101s; these included the addition of electronic warfare pods and a new electro-optical system, in advance of a deployment in Afghanistan in 2014. In September 2013, Danish AW101s were to receive L-3 Wescam MX-15 electro-optical/infrared (EO/IR) sensors; SAR aircraft already carry the FLIR Systems Star Safire II EO/IR sensor.


title: AgustaWestland AW101

text: On 25 October 2007, a project started that had the intent to replace all Westland Sea King search and rescue helicopters with new rescue helicopters by 2020. On 19 December 2013, a contract was signed between AgustaWestland and the government, for the purchase of 16 AW101 helicopters. The agreement came about after fierce competition between different manufacturers to satisfy the Norwegian requirements. Participants were AgustaWestland, Eurocopter, NHIndustries, Sikorsky Aircraft Corporation and Boeing. The government considered that AgustaWestland AW101 met the requirements and specifications in the best possible way.


title: AgustaWestland AW101

text: On 12 June 2017, Per-Willy Amundsen, Minister of Justice and Public Security, announced the opening of Leonardo's AW101 Norway Training Centre at Stavanger Sola Air Station. The training centre includes an AW101 Full Flight Simulator (FFS), jointly developed by Leonardo and CAE to Level D, which is a CAE Series 3000 device, along with an AW101 SAR console training system linked to the FFS to provide rear crew training. The first training course at the centre started prior to delivery of the first rotorcraft. The training center will be used by both Norwegian and foreign AW101 customers.


title: AgustaWestland AW101

text: The first AW101 was delivered in November 2017. The Norwegian AW101s officially started operating in the rescue role on 1 September 2020. The Sea Kings will be phased out gradually until the middle of 2023, after 47 years of service. The AW101 is named "SAR Queen" in Norwegian service.


title: AgustaWestland AW101

text: The Portuguese Air Force had purchased 12 Merlins under a €446 million contract, the first of which was delivered on 22 December 2004. The type has been used to conduct transport, search and rescue, and maritime surveillance missions, progressively replacing the Aérospatiale Puma previously tasked with these missions. The main role of Portuguese AW101s is to perform search and rescue missions within Portugal's maritime zone. They are operated by 751 Squadron and are kept on constant alert at three bases: Montijo near Lisbon, Lajes Field on the Azores, and Porto Santo Island.


title: AgustaWestland AW101

text: The Japan Maritime Self-Defense Force (JMSDF) ordered 14 aircraft in 2003 to use in both the airborne mine countermeasures (AMCM) and transport roles. The AW101 was modified by Kawasaki Heavy Industries, and the Japan Defense Agency designated the model MCH-101. Special features include the automated folding of the rotor and tail. For the mine-hunting role, the MCH-101 has been outfitted with Northrop Grumman's AQS-24A airborne mine-hunting system and AN/AES-1 Airborne Laser Mine Detection System (ALMDS) for a complete surface-to-bottom mine detection capability, as well as Mk-104 acoustic mine sweeping gear.


title: AgustaWestland AW101

text: In 2002, AgustaWestland, Kawasaki and Marubeni entered a general agreement for cooperation; Kawasaki began the assembly of both the CH-101 and the MCH-101 in 2003. Kawasaki also began licensed production of the RTM322 engines in 2005. In a separate agreement between Marubeni and AgustaWestland, a supply depot was established in Japan to support the MCH-101 and CH-101 fleets. The first MCH-101 was delivered to the JMSDF on 3 March 2006.


title: AgustaWestland AW101

text: The MCH-101 will replace the MH-53E (S-80-M-1) in the AMCM role. The CH-101 will operate in the transport/support role for Antarctic expeditions, replacing the Sikorsky S-61A, and will be working in coordination with the Ministry of Education, Culture, Sports, Science and Technology.


title: AgustaWestland AW101

text: After a whistle-blower alleged that the MSDF's preference had been improperly changed an investigation was launched. On 16 December 2016 the Japanese Ministry of Defense (the Defense Agency having been upgraded to a ministry in 2007) stated that it had not confirmed lobbying efforts but the ministry admonished Tomohisa Takei, the JMSDF chief of staff, for mentioning the MCH-101 by name during the procurement process to his subordinates. This had come after MSDF officials had reported that the Mitsubishi-built SH helicopters may be best.


title: AgustaWestland AW101

text: AgustaWestland developed a specialised luxury variant, the AW101 VVIP (Very Very Important Person, i.e. a head of state), aimed at business and VIP customers. As of April 2009, 15% of all AW101s sold were for VIP purposes. By September 2013, customers operating the VIP variant included Saudi Arabia, Algeria, Nigeria and Turkmenistan.


title: AgustaWestland AW101

text: The AW101 was being acquired by the United States Marine Corps under the VXX program as a replacement for the Presidential Marine One helicopters. Designated "VH-71 Kestrel", the variant was heavily customised and equipped with various self-defense systems. However the programme encountered significant cost overruns and political opposition, which led to the procurement being scrapped in June 2009. After the cancellation, the delivered helicopters were sold to Canada for $164 million, where they were used as source of spare parts for its fleet of Agusta Westland CH-149 Cormorant search-and-rescue helicopters. Separately, the Marine Corps had also conducted studies into the adoption of the EH101 as a fallback option to the Bell-Boeing V-22 Osprey tiltrotor during the 1990s.


title: AgustaWestland AW101

text: In April 2009, India ordered 12 AW101 to serve as executive transport helicopters for the Indian President and Prime Minister. The selection followed field trial assessments between the AW101 and the Sikorsky S-92 held in 2008. However, the procurement was put on hold and subsequently cancelled due to the 2013 Indian helicopter bribery scandal, in which Finmeccanica, AgustaWestland's parent company, were accused of using bribery to win the contract. The three helicopters delivered as part of the contract may be returned to the manufacturer as part of the arbitration process.


title: Tower of Hanoi

text: The Tower of Hanoi (also called The problem of Benares Temple or Tower of Brahma or Lucas' Tower and sometimes pluralized as Towers, or simply pyramid puzzle) is a mathematical game or puzzle consisting of three rods and a number of disks of various diameters, which can slide onto any rod. The puzzle begins with the disks stacked on one rod in order of decreasing size, the smallest at the top, thus approximating a conical shape. The objective of the puzzle is to move the entire stack to the last rod, obeying the following rules:


title: Tower of Hanoi

text: With 3 disks, the puzzle can be solved in 7 moves. The minimal number of moves required to solve a Tower of Hanoi puzzle is 2 − 1, where "n" is the number of disks.


title: Tower of Hanoi

text: The puzzle was introduced to the West by the French mathematician Édouard Lucas in 1883. Numerous myths regarding the ancient and mystical nature of the puzzle popped up almost immediately, including one about an Indian temple in Kashi Vishwanath containing a large room with three time-worn posts in it, surrounded by 64 golden disks. Acting out the command of an ancient prophecy, Brahmin priests have been moving these disks in accordance with the immutable rules of Brahma since that time. The puzzle is therefore also known as the Tower of Brahma. According to the legend, when the last move of the puzzle is completed, the world will end.


title: Tower of Hanoi

text: If the legend were true, and if the priests were able to move disks at a rate of one per second, using the smallest number of moves, it would take them 2 − 1 seconds or roughly 585 billion years to finish, which is about 42 times the current age of the universe.


title: Tower of Hanoi

text: There are many variations on this legend. For instance, in some tellings, the temple is a monastery, and the priests are monks. The temple or monastery may be in various locales including Hanoi, and may be associated with any religion. In some versions, other elements are introduced, such as the fact that the tower was created at the beginning of the world, or that the priests or monks may make only one move per day.


title: Tower of Hanoi

text: The puzzle can be played with any number of disks, although many toy versions have around 7 to 9 of them. The minimal number of moves required to solve a Tower of Hanoi puzzle is , where "n" is the number of disks.


title: Tower of Hanoi

text: A simple solution for the toy puzzle is to alternate moves between the smallest piece and a non-smallest piece. When moving the smallest piece, always move it to the next position in the same direction (to the right if the starting number of pieces is even, to the left if the starting number of pieces is odd). If there is no tower position in the chosen direction, move the piece to the opposite end, but then continue to move in the correct direction. For example, if you started with three pieces, you would move the smallest piece to the opposite end, then continue in the left direction after that. When the turn is to move the non-smallest piece, there is only one legal move. Doing this will complete the puzzle in the fewest moves.


title: Tower of Hanoi

text: Considering those constraints after the first move, there is only one legal move at every subsequent turn.


title: Tower of Hanoi

text: The sequence of these unique moves is an optimal solution to the problem equivalent to the iterative solution described above.


title: Tower of Hanoi

text: The key to solving a problem recursively is to recognize that it can be broken down into a collection of smaller sub-problems, to each of which "that same general solving procedure that we are seeking" applies, and the total solution is then found in some "simple" way from those sub-problems' solutions. Each of these created sub-problems being "smaller" guarantees that the base case(s) will eventually be reached. Thence, for the Towers of Hanoi:


title: Tower of Hanoi

text: Assuming all "n" disks are distributed in valid arrangements among the pegs; assuming there are "m" top disks on a "source" peg, and all the rest of the disks are larger than "m", so they can be safely ignored; to move "m" disks from a source peg to a "target" peg using a "spare" peg, without violating the rules:


title: Tower of Hanoi

text: The full Tower of Hanoi solution then consists of moving "n" disks from the source peg A to the target peg C, using B as the spare peg.


title: Tower of Hanoi

text: This approach can be given a rigorous mathematical proof with mathematical induction and is often used as an example of recursion when teaching programming.


title: Tower of Hanoi

text: As in many mathematical puzzles, finding a solution is made easier by solving a slightly more general problem: how to move a tower of "h" (height) disks from a starting peg "f" = A (from) onto a destination peg "t" = C (to), B being the remaining third peg and assuming "t" ≠ "f". First, observe that the problem is symmetric for permutations of the names of the pegs (symmetric group "S"). If a solution is known moving from peg A to peg C, then, by renaming the pegs, the same solution can be used for every other choice of starting and destination peg. If there is only one disk (or even none at all), the problem is trivial. If "h" = 1, then simply move the disk from peg A to peg C. If "h" > 1, then somewhere along the sequence of moves, the largest disk must be moved from peg A to another peg, preferably to peg C. The only situation that allows this move is when all smaller "h" − 1 disks are on peg B. Hence, first all "h" − 1 smaller disks must go from A to B. Then move the largest disk and finally move the "h" − 1 smaller disks from peg B to peg C. The presence of the largest disk does not impede any move of the "h" − 1 smaller disks and can be temporarily ignored. Now the problem is reduced to moving "h" − 1 disks from one peg to another one, first from A to B and subsequently from B to C, but the same method can be used both times by renaming the pegs. The same strategy can be used to reduce the "h" − 1 problem to "h" − 2, "h" − 3, and so on until only one disk is left. This is called recursion. This algorithm can be schematized as follows.


title: Tower of Hanoi

text: Identify the disks in order of increasing size by the natural numbers from 0 up to but not including "h". Hence disk 0 is the smallest one, and disk "h" − 1 the largest one.


title: Tower of Hanoi

text: The following is a procedure for moving a tower of "h" disks from a peg A onto a peg C, with B being the remaining third peg:


title: Tower of Hanoi

text: By means of mathematical induction, it is easily proven that the above procedure requires the minimal number of moves possible and that the produced solution is the only one with this minimal number of moves. Using recurrence relations, the exact number of moves that this solution requires can be calculated by: formula_1. This result is obtained by noting that steps 1 and 3 take formula_2 moves, and step 2 takes one move, giving formula_3.


title: Tower of Hanoi

text: The list of moves for a tower being carried from one peg onto another one, as produced by the recursive algorithm, has many regularities. When counting the moves starting from 1, the ordinal of the disk to be moved during move "m" is the number of times "m" can be divided by 2. Hence every odd move involves the smallest disk. It can also be observed that the smallest disk traverses the pegs "f", "t", "r", "f", "t", "r", etc. for odd height of the tower and traverses the pegs "f", "r", "t", "f", "r", "t", etc. for even height of the tower. This provides the following algorithm, which is easier, carried out by hand, than the recursive algorithm.


title: Tower of Hanoi

text: For the very first move, the smallest disk goes to peg "t" if "h" is odd and to peg "r" if "h" is even.


title: Tower of Hanoi

text: With this knowledge, a set of disks in the middle of an optimal solution can be recovered with no more state information than the positions of each disk:


title: Tower of Hanoi

text: Disk positions may be determined more directly from the binary (base-2) representation of the move number (the initial state being move #0, with all digits 0, and the final state being with all digits 1), using the following rules:


title: Tower of Hanoi

text: The source and destination pegs for the "m"th move can also be found elegantly from the binary representation of "m" using bitwise operations. To use the syntax of the C programming language, move "m" is from peg codice_1 to peg codice_2, where the disks begin on peg 0 and finish on peg 1 or 2 according as whether the number of disks is even or odd. Another formulation is from peg codice_3 to peg codice_4.


title: Tower of Hanoi

text: Furthermore, the disk to be moved is determined by the number of times the move count ("m") can be divided by 2 (i.e. the number of zero bits at the right), counting the first move as 1 and identifying the disks by the numbers 0, 1, 2, etc. in order of increasing size. This permits a very fast non-recursive computer implementation to find the positions of the disks after m moves without reference to any previous move or distribution of disks.


title: Tower of Hanoi

text: The operation, which counts the number of consecutive zeros at the end of a binary number, gives a simple solution to the problem: the disks are numbered from zero, and at move "m", disk number count trailing zeros is moved the minimal possible distance to the right (circling back around to the left as needed).


title: Tower of Hanoi

text: The binary numeral system of Gray codes gives an alternative way of solving the puzzle. In the Gray system, numbers are expressed in a binary combination of 0s and 1s, but rather than being a standard positional numeral system, the Gray code operates on the premise that each value differs from its predecessor by only one (and exactly one) bit changed.


title: Tower of Hanoi

text: If one counts in Gray code of a bit size equal to the number of disks in a particular Tower of Hanoi, begins at zero and counts up, then the bit changed each move corresponds to the disk to move, where the least-significant bit is the smallest disk, and the most-significant bit is the largest.


title: Tower of Hanoi

text: This technique identifies which disk to move, but not where to move it to. For the smallest disk, there are always two possibilities. For the other disks there is always one possibility, except when all disks are on the same peg, but in that case either it is the smallest disk that must be moved or the objective has already been achieved. Luckily, there is a rule that does say where to move the smallest disk to. Let "f" be the starting peg, "t" the destination peg, and "r" the remaining third peg. If the number of disks is odd, the smallest disk cycles along the pegs in the order "f" → "t" → "r" → "f" → "t" → "r", etc. If the number of disks is even, this must be reversed: "f" → "r" → "t" → "f" → "r" → "t", etc.


title: Tower of Hanoi

text: The position of the bit change in the Gray code solution gives the size of the disk moved at each step: 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1, ... , a sequence also known as the ruler function, or one more than the power of 2 within the move number. In the Wolfram Language, codice_5 gives moves for the 8-disk puzzle.


title: Tower of Hanoi

text: The game can be represented by an undirected graph, the nodes representing distributions of disks and the edges representing moves. For one disk, the graph is a triangle:


title: Tower of Hanoi

text: The nodes at the vertices of the outermost triangle represent distributions with all disks on the same peg.


title: Tower of Hanoi

text: For h + 1 disks, take the graph of h disks and replace each small triangle with the graph for two disks.


title: Tower of Hanoi

text: The sides of the outermost triangle represent the shortest ways of moving a tower from one peg to another one. The edge in the middle of the sides of the largest triangle represents a move of the largest disk. The edge in the middle of the sides of each next smaller triangle represents a move of each next smaller disk. The sides of the smallest triangles represent moves of the smallest disk.


title: Tower of Hanoi

text: In general, for a puzzle with "n" disks, there are 3 nodes in the graph; every node has three edges to other nodes, except the three corner nodes, which have two: it is always possible to move the smallest disk to one of the two other pegs, and it is possible to move one disk between those two pegs "except" in the situation where all disks are stacked on one peg. The corner nodes represent the three cases where all the disks are stacked on one peg. The diagram for "n" + 1 disks is obtained by taking three copies of the "n"-disk diagram—each one representing all the states and moves of the smaller disks for one particular position of the new largest disk—and joining them at the corners with three new edges, representing the only three opportunities to move the largest disk. The resulting figure thus has 3 nodes and still has three corners remaining with only two edges.


title: Tower of Hanoi

text: As more disks are added, the graph representation of the game will resemble a fractal figure, the Sierpiński triangle. It is clear that the great majority of positions in the puzzle will never be reached when using the shortest possible solution; indeed, if the priests of the legend are using the longest possible solution (without re-visiting any position), it will take them 3 − 1 moves, or more than 10 years.


title: Tower of Hanoi

text: Incidentally, this longest non-repetitive path can be obtained by forbidding all moves from "a" to "c".


title: Tower of Hanoi

text: If all moves must be between adjacent pegs (i.e. given pegs A, B, C, one cannot move directly between pegs A and C), then moving a stack of "n" disks from peg A to peg C takes 3 − 1 moves. The solution uses all 3 valid positions, always taking the unique move that does not undo the previous move. The position with all disks at peg B is reached halfway, i.e. after (3 − 1) / 2 moves.


title: Tower of Hanoi

text: In Cyclic Hanoi, we are given three pegs (A, B, C), which are arranged as a circle with the clockwise and the counterclockwise directions being defined as A – B – C – A and A – C – B – A respectively. The moving direction of the disk must be clockwise. It suffices to represent the sequence of disks to be moved. The solution can be found using two mutually recursive procedures:


title: Tower of Hanoi

text: Let C(n) and A(n) represent moving n disks clockwise and counterclockwise, then we can write down both formulas:


title: Tower of Hanoi

text: 1)The move-patterns of transferring a tower of disks from a peg to another peg are symmetric with respect to the center points.


title: Tower of Hanoi

text: Although the three-peg version has a simple recursive solution long been known, the optimal solution for the Tower of Hanoi problem with four pegs (called Reve's puzzle) was not verified until 2014, by Bousch.


title: Tower of Hanoi

text: However, in case of four or more pegs, the Frame–Stewart algorithm is known without proof of optimality since 1941.


title: Tower of Hanoi

text: For the formal derivation of the exact number of minimal moves required to solve the problem by applying the Frame–Stewart algorithm (and other equivalent methods), see the following paper.


title: Tower of Hanoi

text: The so-called Towers of Bucharest and Towers of Klagenfurt game configurations yield ternary and pentary Gray codes.


title: Tower of Hanoi

text: The entire process takes formula_17 moves. Therefore, the count formula_7 should be picked for which this quantity is minimum. In the 4-peg case, the optimal formula_7 equals formula_20, where formula_21 is the nearest integer function. For example, in the UPenn CIS 194 course on Haskell, the first assignment page lists the optimal solution for the 15-disk and 4-peg case as 129 steps, which is obtained for the above value of "k".


title: Tower of Hanoi

text: This algorithm is presumed to be optimal for any number of pegs; its number of moves is 2 (for fixed "r").


title: Tower of Hanoi

text: A curious generalization of the original goal of the puzzle is to start from a given configuration of the disks where all disks are not necessarily on the same peg and to arrive in a minimal number of moves at another given configuration. In general, it can be quite difficult to compute a shortest sequence of moves to solve this problem. A solution was proposed by Andreas Hinz and is based on the observation that in a shortest sequence of moves, the largest disk that needs to be moved (obviously one may ignore all of the largest disks that will occupy the same peg in both the initial and final configurations) will move either exactly once or exactly twice.


title: Tower of Hanoi

text: The mathematics related to this generalized problem becomes even more interesting when one considers the "average" number of moves in a shortest sequence of moves between two initial and final disk configurations that are chosen at random. Hinz and Chan Tat-Hung independently discovered (see also