Keys "s"=save "l"=load "b"=back once
If your move empties a rank or file, it disappears permanently.
Pawns can make the initial double move only if there are still eight ranks.
To save programming space, I decided that all pawn promotions produce queens, and I have disallowed castling if any involved columns are lost.
Thanks to Emiliano Venturini for help with the debugging (Oct. 2003).
These are simple illustrations rather than strong opponents.
Bug reports? -- Thank you! Keep them coming!