pieces can be promoted only upon capturing an opponent piece. Promotion is optional if the captured piece is unpromoted but mandatory if the captured piece is promoted. This is particularly important, as many pieces' promoted forms are in fact far weaker, so these pieces will often avoid capturing promoted pieces. This variant is also unique in that the king can be promoted as well: it is promoted to a very powerful piece called the emperor, which can jump to any unprotected square on the board. Many large variants (including chu shogi, dai shogi and maka dai dai shogi, as well as sho shogi which is a direct predecessor of standard shogi) have a piece known as the drunk elephant, which is promoted to a prince. The prince has exactly the same movements as the king and is also a royal piece; this means that, when a drunk elephant is promoted, the player has two royal pieces, and the opponent must capture both to win the game. Xiangqi Xiangqi has a rule that resembles promotion: the soldier, which moves and captures one point vertically forward, gains the additional ability to move and capture one point horizontally after crossing into the opposing half of the board. This does not change the piece's identity, however. See also Notes References Bibliography External links Underpromotion in Chess by Edward Winter Chess terminology Rules of chess