Around 1925, J. L. Naylor and E. Ower invented this game for four players. The game was mentioned in Pritchard's The Encyclopedia of Chess Variants.
The game is played by four players, forming two teams of two players each. Each player owns ten pieces: one king, one queen, one rook, one knight, one bishop, and five pawns.
The game is played on a board with eight rows of ten squares. The opening setup is the following:
Player A: King d1; Queen e1; Rook a1; Knight b1; Bishop c1; Pawn a2, b2, c2, d2, e2.
Player B: King g1; Queen f1; Rook h1; Knight j1; Bishop i1; Pawn a2, b2, c2, d2, e2.
Player C: King d8; Queen e8; Rook a8; Knight b8; Bishop c8; Pawn a7, b7, c7, d7, e7.
Player D: King g8; Queen f8; Rook h8; Knight j8; Bishop i8; Pawn
a7, b7, c7, d7, e7.
Player A (down left) and B (down right) form a team, and player C (upper left) and D (upper right) form a team.
The order of play is: player B starts, then player D, then player A, then player C, then player B again, etc.
The object of the game is to mate both opponents.
The pieces of a mated player are frozen. The player may not move, as long as his king is in a mated position. Moreover, these pieces may not be taken. When the mate is removed, then the player can move again with his pieces. When one opponent is mated, a player can move such that the mate is lifted; when doing so he may with that move not take a piece of that opponent.
Frozen pieces do not give check. Also, pieces of ones partner do not give check.
The game is drawn when one player is stalemated.