Touch-move rule the player touches his rook at the same time as touching the king, he must castle with that rook if it is legal to do so. If the player completes a two-square king move without touching a rook, the player must move the correct rook accordingly if castling on that side is legal. Otherwise, the move must be withdrawn and another king move made. When a pawn is moved to its eighth , once the player takes his hand off the pawn, a different move of the pawn can no longer be substituted. However, the move is not complete until
Three-player chess avoid this "petty diplomacy" problem by determining the victor as the player who first delivers checkmate, with the third player losing in addition to the checkmated player. Other solutions have been tried as well. Some variants use a board with hexagonal cells. Usually three bishops per side are included, to cover all cells of the hex playing field. Pieces move usually as in one of the versions of hexagonal chess. Some variants use a hexagonal-shaped board with quadrilateral cells (see example in the photo). Some variants have used other board shapes with quadrilateral cells. Triangular cells not on the perimeter