In Pilgrim Chess the rules are the same as in orthodox chess, except that one extra piece (or two) per player is placed in the reserve. Standard chess is included as an option.

Before starting, the players must decide whether they want to use the extra piece. To make a decision, press on the little black square. Only if both players choose not to use the extra piece, then it becomes a regular game of chess. If white turns down the extra piece, then black can overrule this. (Should both players exclude the external piece(s), then they must be removed by clicking on them.) Each variant features a particular extra piece. Choose your own favourite. Right-click on a piece to get more information.

If players have elected to include external pieces, they must now be placed on the file on which the player intends to introduce the piece(s). If, for instance, the player places the external piece on the queen file (behind the queen), then the piece is automatically introduced on the queen pawn's initial square when the queen pawn moves away, whether it moves one or two steps. Should a pawn on the initial position be captured (exchanged), then the player has forfeited his right to introduce an external piece placed behind it.