Ludus latrunculorum

Ludus latrunculorum, latrunculi, or simply latrones ("the game of brigands", from "latrunculus", diminutive of "latro", mercenary or highwayman) was a two-player strategy board game played throughout the Roman Empire. It is said to resemble chess or draughts, but is generally accepted to be a game of military tactics. Because of the scarcity of sources, reconstruction of the game's rules and basic structure is difficult, and therefore there are multiple interpretations of the available evidence.
History.
Sources.
The game of "latrunculi" is believed to be a variant of earlier Greek games known variously as "Petteia", "pessoí", "psêphoi", "poleis" and "pente grammaí", to which references are found as early as Homer's time. In Plato's "Republic", Socrates' opponents are compared to "bad Petteia players, who are finally cornered and made unable to move." In the "Phaedrus", Plato writes that these games come from Egypt, and a draughts-like game called Seega is known to have been played in ancient Egypt.
In his "Onomasticon", the Greek writer Julius Pollux describes "Poleis" as follows:
The game played with many pieces is a board with spaces disposed among lines: the board is called the "city" and each piece is called a "dog;" the pieces are of two colors, and the art of the game consists in taking a piece of one color by enclosing it between two of the other color.
Among the Romans, the first mention of "latrunculi" is found in the Roman author Varro (116–27 BC), in the tenth book of his "De Lingua Latina" ("On the Latin Language"), where he mentions the game in passing, comparing the grid on which it is played to the grid used for presenting declensions. An account of a game of "latrunculi" is given in the 1st-century AD "Laus Pisonis":
When you are weary with the weight of your studies, if perhaps you are pleased not to be inactive but to start games of skill, in a more clever way you vary the moves of your counters on the open board, and wars are fought out by a soldiery of glass, so that at one time a white counter traps blacks, and at another a black traps whites. Yet what counter has not fled from you? What counter gave way when you were its leader? What counter [of yours] though doomed to die has not destroyed its foe? Your battle line joins combat in a thousand ways: that counter, flying from a pursuer, itself makes a capture; another, which stood at a vantage point, comes from a position far retired; this one dares to trust itself to the struggle, and deceives an enemy advancing on its prey; that one risks dangerous traps, and, apparently entrapped itself, counter traps two opponents; this one is advanced to greater things, so that when the formation is broken, it may quickly burst into the columns, and so that, when the rampart is overthrown, it may devastate the closed walls. Meanwhile, however keenly the battle rages with cut-up soldiers, you conquer with a formation that is full, or bereft of only a few soldiers, and each of your hands rattles with its band of captives.
Allusions to the game are found in the works of such writers as Martial and Ovid and they provide ideal evidence as to the method of capture used in the game with passages such as: "unus cum gemino calculus hoste perit", Ov. "Ars amatoria" 3.358 ("when one counter perishes by a twin foe"); "cum medius gemino calculus hoste perit", Ov. "Tristia" 2.478 ("when a counter perishes in the midst by a twin foe"); and "calculus hae (sc. tabula) gemino discolor hoste perit", Mart. 14.17.2 ("a counter of differing colour perishes on this [board] with a twin enemy").
Ovid also writes about the efforts to rescue an isolated piece away from the others: "how the different colored soldier marches forth in a straight line; when a piece caught between two adversaries is imperiled, how one advancing may be skilful to attack and rescue a piece moved forward, and retreating may move safely, not uncovered" (Tristia II 477–480). According to Ulrich Schädler, this indicates that the pieces in the game only moved one space per turn, instead of using the Rook's move, otherwise an isolated piece's escape would have been relatively easy. Schädler also deduces from this that pieces were able to jump over other pieces into an empty square beyond, otherwise a rescuing piece could end up blocking the other piece needing rescue.
The last mention of "latrunculi" that survives from the Roman period is in the "Saturnalia" of Macrobius.
For a long time, it was thought that the eighteenth book of Isidore of Seville's "Etymologiae" contains a reference to "latrunculi", and this was used to argue that the pieces on either side were of different powers and classes like the pieces in chess. R. G. Austin has argued, however, that the passage from Isidore on which this belief was based refers to an early form of Tabula. 
Chess.
"Latrunculi" as well as "latrones" is mentioned many times in Ruy López de Segura's classic 1561 work "Libro de la invencion liberal y arte del juego del axedrez", also referring to mentions in Jacobus de Cessolis's sermons on the theme of chess in the later thirteenth century.
Latrunculi is mentioned on the first page of Philidor's classic 1774 work "Analysis of the Game of Chess."
Myron J. Samsin and Yuri Averbakh have both supported the theory that "Petteia" may have had an influence on the historical development of early Chess, particularly the movement of the pawns. "Petteia" games could have certainly been brought to central Asia and northern India during the rule of the Greco-Bactrian Kingdom and Indo-Greek Kingdom which were known to combine Indian and Greek elements in their art, coinage, and religious practices.
When chess came to Germany, the chess terms for "chess" and "check" (which had originated in Persian) entered the German language as "Schach". But "Schach" was already a native German word for robbery. As a result, "ludus latrunculorum" was often used as a medieval Latin name for chess.
Board geometry.
Since, in archaeological excavations, it is usually hard to tell what game a gridded board was used for, it is hard to determine the size of the board on which "latrunculi" was played. R. C. Bell, writing in 1960, mentioned boards of 7×8, 8×8, and 9×10 squares as common in Roman Britain. W. J. Kowalski refers to the "Stanway Game", an archeological find of 1996 in Stanway, Essex, England, and believes the game was played on a board of 8×12 squares; the same size that was used a thousand years later for courier chess. He later allowed a board of 10×11 squares. The rules may have varied much across the width of the Roman Empire and through time.
Game rule reconstructions.
Ulrich Schädler's reconstruction (2001).
Use a normal checkerboard with 8×8 squares. The two players agree about the number of pieces, at least 16, but not more than 24 for each player. If the board is larger, then the number of pieces increases too. Use pieces such as coins or hemispheres with different sides that can be flipped.
Museum Quintana reconstruction.
These are the rules from the in Künzing (pictured above):
Similar games.
In China the various board games in the family of Fang Qi have similar rules. Typically board size varies from 4×4 in Korea (Gonu) to 17×17 in Tibet. Most varieties have the initial "Placing Stone" phase, followed by the "Removing Stone" phase (if any), and then finally the "Capturing Stone" phase.