xiangqi show the same development trend as has occurred for international chess: they are usually console applications (called engines) which communicate their moves in text form through some standard protocol. For displaying the board graphically, they then rely on a separate graphical user interface (GUI). Through such standardization, many different engines can be used through the same GUI, which can also be used for automated play of different engines against each other. Popular protocols are UCI (Universal Chess Interface), UCCI (Universal Chinese Chess Interface), Qianhong (QH) protocol, and WinBoard/XBoard (WB) protocol (the latter two named after the GUIs that implemented them). There now exist many dozens of xiangqi engines supporting one or more of these protocols, including some commercial engines. Variations Blitz chess Each player only has around 5–10 minutes each. Manchu chessInvented during the Manchu-led Qing dynasty. Red horses, cannons, and one of the chariots are absent, but the remaining chariot can be played as horses and cannons as well. Supply chess Similar to the Western chess variant Bughouse chess, this variant features the ability to re-deploy captured pieces, similar to a rule in shogi. Four players play as two-person teams in two side-by-side games. One teammate plays Black and other plays Red. Any piece obtained by capturing the opponent's piece is given to the teammate for use in the other game. These pieces can be deployed by the teammate to give him an advantage over the other player, so long as the piece starts on the player's own side of the board and does not cause the opponent to be in check. Formation Similar to Fischer Random Chess, one player's pieces are placed randomly on one side of the river, except for the generals and advisors, which must be at their usual positions, and the elephants, which must start at two of the seven points they can normally reach. The other player's pieces are set up to mirror the first's. All other rules are the same. Banqi This variation is more well known in Hong Kong than in mainland China. It uses the xiangqi pieces and board, but does not follow any of its rules, bearing more of a resemblance to the Western game Stratego as well as the Chinese game Luzhanqi. Variations played with special boards or pieces There are many versions of three-player xiangqi, or san xiangqui, all played on special boards. San Guo Qi "Game