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Extra Move Chess. Double-move variant based on limitations of Zillions of Games. (8x8, Cells: 64) [All Comments] [Add Comment or Rating]
Fergus Duniho wrote on 2015-04-02 UTC
Thank goodness I wrote the notes on this game when I made this page ten years ago. It helped me figure out what my ZRF code was doing, so that I could fix a bug I just discovered recently. The bug concerned the code I wrote to make blocks made on the second part of a move ineffective. It inadvertently allowed a Rook check when the checking player's last move was to move a Pawn forward. It now checks the side of the piece last moved, confirming that it belongs to the other side, and it now blocks checks on the space the last piece to move moved from.

The ZRF still allows a player to make moves that do not end check on his King. But it's because of this limitation that the rules and ZRF are designed to prevent the second move from effectively rescuing a King from check. This assures that any first move that leaves one's King in check will automatically end the game in checkmate. Game Courier can stop this, but when playing Zillions, it's up to the player to not accidentally move into checkmate. Of course, with Zillions, the player has the option of undoing his move and continuing on.