Pawn (chess) bishops, ten rooks or nine queens on the board at the same time. While this extreme would almost never occur in practice, in game 11 of their 1927 world championship match, José Raúl Capablanca and Alexander Alekhine each had two queens in play at once (from move 65 through the end on move 66). While some finer sets do include an extra queen of each color, most standard chess sets do not come with additional pieces, so the physical piece used to replace a promoted pawn on the board is usually one that was previously captured. When the correct piece
Chess and is provably less than 10, with a game-tree complexity of approximately 10. The game-tree complexity of chess was first calculated by Claude Shannon as 10, a number known as the Shannon number. Typically an average position has thirty to forty possible moves, but there may be as few as zero (in the case of checkmate or stalemate) or (in a constructed position) as many as 218. Chess has inspired many combinatorial puzzles, such as the knight's tour and the eight queens puzzle. The idea of creating a chess-playing machine dates to the 18th century; around 1769, the chess-playing automaton