Chess

Chess in Code Geass seems to follow from the same basic rules, objective and design as Chess in the real world. However, there was an exception when Lelouch played against Schneizel, in which the Prime Minister made a move that left his king open to be captured, even though there were other moves available. The game kept going on, although that would be an illegal move of Chess in the real world.

Chess in Code Geass
Chess seems to play an important role in Britannian Nobility as a way of developing and demonstrating tactical skill. Chess was rarely shown in the series, only appearing in order to show Lelouch's considerable intellect or, later, to show that Schneizel's strategic prowess was equal to that of Lelouch. Chess is a form of gambling, which Lelouch is a master of and with an infamous reputation. Depending on the situation Lelouch would alternate between offering his services as an aide for other chess players to taking part in actual games himself. Lelouch himself is a masterful player, having previously lost only to Mao, as a result of his Geass allowing him to read and forestalled Lelouch's moves, and Schneizel, due to the former's considerable talent at strategy and subtle manipulation. Lelouch preferred an aggressive style, counting on surprise and complete shock on the part of his enemies, usually by aggressive use of his king, a move that normally would be a very poor choice in the actual game, this often led him to quote "If the king does not lead, how can he expect his subordinates to follow," effectively demonstrating his own feelings toward command. This was often used as a motif and comedic foil referencing the king's ability for limited movement, whilst allowing a comment on Lelouch's poor physical ability. Lelouch was also known to cut class during school days in order to play chess to supplement his income and as an attempt to fight his considerable boredom as he sought for a "more challenging opponent."

Chess is also an important symbol throughout Code Geass. Lelouch thinks of all his actions as Zero, both on and off the battlefield, as moves on a Chess board. His helmet is similar in appearance to the Black King piece shown in Code Geass chessboards, which is also why his terrorist organization is called the Black Knights. Alternately, the Britannian military uses a white color scheme, and Lelouch's rival Suzaku Kururugi pilots the Knightmare Frame, Lancelot, named after a famous Arthurian Knight. The knight is a highly valuable piece in chess, and since Suzaku fights on the Britannian side, it refers to how Lelouch sees his friend as his greatest foe.

For more information including rules and history, see the Wikipedia article of the actual game of Chess

List of Known Chess Matches in the Code Geass Anime

 * Lelouch's employer (Black) vs Unknown Nobleman (White). Result: Inconclusive (Replaced by Lelouch). Appearance: Episode 1 Season 1
 * Lelouch (Black) vs Unnamed Nobleman (White). Replaced and Continued. Result: Victory for Lelouch. Appearance: Episode 1 Season 1
 * Lelouch (Black) vs Mao (White). Result: Inconclusive (Game Incomplete). Appearance: Episode 16 Season 1
 * Lelouch (White) vs "The Black King" (Black). Result: Victory for Lelouch. Appearance: Episode 1 Season 2
 * Lelouch (Black) vs Schneizel (White). Result: Inconclusive (Game Incomplete), interrupted by Nina Einstein. Appearance: Episode 9 Season 2

List of Known Chess Players
Holy Britannian Empire Chinese Federation United Federation of Nations
 * Lelouch Lamperouge/Lelouch vi Britannia
 * Clovis la Britannia
 * Schneizel el Britannia
 * Lelouch's employer
 * Unnamed Noble
 * The Black King
 * Mao
 * Lelouch Lamprouge/Lelouch vi Britannia (As Zero)

Trivia

 * In Season 2 episode 9, Schneizel intentionally uses his king to checkmate himself. This is actually illegal in chess and making such a move would result in his disqualification.