Keys "s"=save "l"=load "b"=back once
One of the best-received variants of four-handed chess is Chessapeak Challenge (link to the commercial producer is now down) which solves one of the major problems of the game by having pawns change directions during their march.
Since I do not have a complete copy of the rules, I called this applet, respectfully, "Chesapeare Four-Handed Chess". Here, I permitted players to capture opponent's units. The game is over when a player on turn cannot make a legal move. This is either checkmate (win for the other side) or stalemate.
The principal website is now down.
These are simple illustrations rather than strong opponents.
Bug reports? -- Thank you! Keep them coming!