The rules as in standard chess, except that you don't see all enemy pieces. You see only positions attacked by your pieces, or positions where your pawns can go to. The capture en-passant is not allowed. The promoted pieces are always visible. You are not told if your king is in check. If you don't move it out of check or put him into check yourself, the opponent can capture him and win the game.
 
To play black, select the second variant: "Dark Chess (Play for Black)" and then switch sides. In the provided endgame variants, dark pieces are located initially on the same positions as yours.
 
For after game replay, press 'Switch Piece Set' button. All pieces in alternative piece set are intentionally visible to let you see what happened in the reality.
 
There are 7 variants in zrf file:

• Dark Chess
• Dark Chess (Play for Black)
• Dark Chess, Pawn Endgame
• Dark Chess, Knight Endgame
• Dark Chess, Bishop Endgame
• Dark Chess, Rook Endgame
• Dark Chess, Queen Endgame