Pirc Defence

The Pirc Defence ( , though often mispronounced as ) is a chess opening characterised by Black responding to 1.e4 with 1...d6 and 2...Nf6, followed by ...g6 and ...Bg7, while allowing White to establish a centre with pawns on d4 and e4. It is named after the Slovenian grandmaster Vasja Pirc.
The Pirc Defence is usually defined by the opening sequence 
This is the most commonly played line after Black responds to 1.e4 with 1...d6. It has been claimed to give rise to somewhat interesting and exciting games, where Black will have but has to be cautious about playing too passively. According to Garry Kasparov, the Pirc Defence is "hardly worth using in the tournaments of the highest category", as it gives White "too many opportunities for anybody's liking".
Description.
The Pirc Defence is a relatively new opening; while it was seen on occasion in the late nineteenth century, it was considered irregular, thus remaining a sideline. The opening began gaining some popularity only after World War II, and by the 1960s it was regarded as , owing in large part to the efforts of Canadian grandmaster Duncan Suttles. Black, in hypermodern fashion, does not immediately stake a claim in the with pawns; rather, Black works to undermine White's centre from the . Its first appearance in a World Championship match was in 1972, when it was played by Bobby Fischer against Boris Spassky at Reykjavík (game 17); the game ended in a draw.
Hooper and Whyld gave a distinct formal definition, 1. d4 d6 2. e4 Nf6 3. Nc3 g6, permuting White's first two moves, although they qualified the definition by remarking that 1. e4 d6 could also to the Pirc. The presence or absence of Black's third move in the Pirc is reported differently, according to the source; with the pawn move 3... g6, Black threatens to fianchetto the King's bishop to g7. Paul van der Sterren therefore described 3... g6 as "the defining move of the Pirc Defence" because the development of the bishop to g7 "creates the same sort of positional tension as the King's Indian Defence."
A distinction is usually drawn between the Pirc and lines where Black delays the development of his knight to f6, or omits it altogether; this is known as the Modern or Robatsch Defence. The tenth edition of "Modern Chess Openings" (1965) grouped the Pirc and Robatsch together as the "Pirc–Robatsch Defense".
Main line: 3...g6.
Austrian Attack: 4.f4.
 
The Austrian Attack begins 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.f4 Bg7 5.Nf3, and was a favourite of Fischer. It is also well respected by Nick de Firmian, the author of "Modern Chess Openings" (). In placing pawns on d4, e4 and f4, White establishes a powerful centre, intending to push in the centre and/or attack on the ; in the main line, Black will usually counter with ...e5, aiming for play against the dark squares and weaknesses created by White's central advance. This direct, aggressive line is one of the most ambitious systems against the Pirc. Jan Timman has played the Austrian successfully with both colours. Yuri Balashov does well with the white pieces, and Valery Beim has an impressive score on the black side.
5...0-0.
The most frequently played move after 5...0-0 is 6.Bd3 (the Weiss Variation), with 6...Nc6 the most common response, though 6...Na6, with the idea of ...Nc7, ...Rb8 and ...b5 became popular in the 1980s after 6...Nc6 was found to offer Black few winning chances. 6.e5 is a try, with unclear consequences, which was much played in the 1960s, though it has never attained popularity at the highest levels. 6.Be2 is another move which was often seen in the 1950s and early 1960s, although the defeat sustained by Fischer in the game given in the sample games spurred White players, including Fischer, to turn to 6.Bd3. In the 1980s, 6.Be2 c5 7.dxc5 Qa5 8.0-0 Qxc5+ 9.Kh1 was revived with more favourable results. 6.Be3 is another possibility, explored in the 1970s.
5...c5.
Black's chief alternative to 5...0-0 lies in an immediate strike against the white centre with 5...c5, to which the usual response is either 6.dxc5 or 6.Bb5+. The former allows 6...Qa5. The latter promises a tactical melee, with a common line being 6.Bb5+ Bd7 7.e5 Ng4 8.e6 (8.h3 or 8.Bxd7+ are other possibilities) 8...fxe6, which was thought bad, until Yasser Seirawan played the move against Gyula Sax in 1988 (8...Bxb5 is the alternative, if Black does not want the forced draw in the main line), continuing 9.Ng5 Bxb5 Now if White tries 10.Nxe6, Black has 10...Bxd4!, ignoring the threat to his queen, in view of 11.Nxd8 Bf2+ 12.Kd2 Be3+ with a draw by perpetual check. White can instead try 11.Nxb5, with complicated play.
White can also essay the sharp 6.e5 against 5...c5, after which 6...Nfd7 7.exd6 0-0 is considered to offer good play for Black.
Classical (Two Knights) System: 4.Nf3.
The Classical (Two Knights) System begins 1.e4 d6 2.d4 Nf6 3.Nc3 g6 4.Nf3 Bg7 5.Be2 0-0 6.0-0. White contents themselves with the 'classical' with pawns at e4 and d4, forgoing the committal move f2–f4 as Black castles and builds a compact structure. Efim Geller, Anatoly Karpov and Evgeni Vasiukov have all successfully used this system for White; Zurab Azmaiparashvili has scored well as Black. This transposes into the Sicilian Dragon after 6...c5 7.Be3 cxd4 8.Nxd4.
The 150 and Argentine Attacks.
The setup f2–f3, Be3 and Qd2 is commonly used against the King's Indian Defence and Dragon Sicilian, and can also be used against the Pirc; indeed, this system is as old as the Pirc itself.
The system 4.f3 was introduced by Argentine players c. 1930 and again in 1950. It was never considered dangerous for Black because of 4.f3 Bg7 5.Be3 c6 6.Qd2 b5. It received a severe blow in about 1985, when Gennady Zaichik showed that Black could castle anyway and play a dangerous gambit with 5...0-0 6.Qd2 e5.
The Argentines feared the sally ...Ng4, though some British players (especially Mark Hebden, Paul Motwani, Gary Lane, later also Michael Adams) came to realise that this was mainly dangerous for Black, therefore playing Be3 and Qd2 in all sorts of move orders, whilst omitting f2–f3. They called this the "150 Attack", because players of this strength (ELO 1800) can easily play this position and get strong play without any theory.
The original Argentine idea probably is only viable after 4.Be3 Bg7 5.Qd2 0-0 6.0-0-0 c6 (or Nc6) 7.f3 b5 8.h4. Black usually does not castle though and prefers 5...c6 or even 4...c6. The question of whether and when to insert Nf3 remains unclear.
Early deviations.
After 1.e4 d6 2.d4 Nf6 3.Nc3, Black has an alternative to 3...g6 (Main line) known as the Pribyl System or Czech Defence, beginning 3...c6. The lines often transpose to the Pirc if Black later plays ...g6; alternatively, Black can play ...Qa5 and ...e5 to challenge White's centre, or expand on the with ...b5.
A common deviation by Black in recent practice is 1.e4 d6 2.d4 Nf6 3.Nc3 e5. This has been tried by many GMs over the years, including Zurab Azmaiparashvili and Christian Bauer. White's 4.dxe5 is known to be equal, and play normally continues 4...dxe5 5.Qxd8+ Kxd8 6.Bc4 Be6 7.Bxe6 fxe6. Instead, White normally transposes to the Philidor Defence with 4.Nf3.
An unusual deviation for Black is 1.e4 d6 2.d4 Nf6 3.Nc3 e6, which can transpose to the Scheveningen Variation of the Sicilian Defence after 4.Nf3 Be7 5.Bb5+ c6 6.Be2 O-O 7.Be3 c5 8.O-O cxd4 9.Nxd4 .
An unusual but quite reasonable deviation for White is 1.e4 d6 2.d4 Nf6 3.f3. At the 1989 Barcelona World Cup event, former world champion Garry Kasparov surprised American grandmaster Yasser Seirawan with this move. After 3...g6 4.c4, an unhappy Seirawan found himself defending the King's Indian Defence for the first time in his life, though he managed to draw the game. Black can avoid a King's Indian with 3...e5, which may lead to an Old Indian type of position after 4.d5, with 3...c5, which may lead to a Benoni type of position after 4.d5 or transpose to Prins variation of the Sicilian Defence after 4.Ne2 cxd4 5.Nxd4, or with 3...d5. This can transpose to the Classical Variation of the French Defence after 4.e5 Nfd7 5.f4 e6 6.Nf3, to the Tarrasch Variation of the French Defence after 4.e5 Nfd7 5.f4 e6 6.c3 c5 7.Nd2 Nc6 8.Ndf3, or even to the Blackmar–Diemer Gambit with an extra tempo for White after 4.Nc3 dxe4 5.Bg5 exf3 6.Nxf3.
"ECO" codes.
Some of the systems employed by White against the Pirc Defence include the following: