Flying chess is a chess variant using a three-dimensional board. It was invented by Dr David Eltis (a noted historian of the Military Revolution) in 1984.
The board used for Flying chess is eight by eight by two, giving a 128-cell board. There can either be markers on "flying" pieces or a second board can be used for the upper level. All pieces start the game as per a standard chess game. Most commonly, two adjacent chess boards are used, one representing the top tier, and the other, the bottom tier.
Kings, queens, and pawns may not go to the higher level. They move as in standard chess, but can also capture an enemy piece that is flying on the square directly above them.
Rooks are among the three pieces that can "fly". They can move on, to, and from the higher level. A rook can make a normal move on any of the two levels: note that the squares it passes over must be empty on the level he moves in. Additionally, a rook can go up when moving on the ground level by making a normal move and then moving diagonally up in the direction the rook moves. They also can go up directly one level. The only way a rook can go down from the upper to the lower level is to directly move one square down.
Bishops are also among the three pieces that can "fly". A bishop can make a standard move on any of the two levels. It can make a normal move on the higher level and then descend diagonally in the direction of movement, or go up from a ground square to the upper level square directly above it, or go down from an upper level square to the ground square immediately below it.
Knights are the third type of "flying" piece. A knight can either make a normal move in any level, or a knight can move in the upper level combined with a direct descend.
All pieces take in the same way as they move. Additionally, each piece can headbutt; when he is in a square on the lower level and a piece of the opponent is in the same square in the upper level, the opponent can take that piece without moving.