Keys "s"=save "l"=load "b"=back once
Pierre Monreal, 1967. A captured unit is replaced on its square of origin if it is unoccupied. For knights and rooks, this is considered to be the square of color matching the capture square. For pawns, the capture file square. I programmed this so that the fifty move rule applies unless a capture actually removes a unit.
These are simple illustrations rather than strong opponents.
Bug reports? -- Thank you! Keep them coming!