In Perier Chess the rules are the same as in orthodox chess, except that one extra piece per player, a Perier, is placed in the reserve. Standard chess is included as an option, thereby maintaining the historical connection. By way of the initial voting procedure, players can decide to play a traditional game.

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.

If players have elected to include external pieces, they may either move a piece or pawn, or drop the extra piece from the reserve. Pieces may only be dropped on the first rank, on an empty square behind a friendly pawn. The friendly pawn is immediately relocated two squares ahead, to a position which must be empty. If these conditions aren't satisfied then the piece cannot be dropped.

Should a player refrain from inserting his extra piece at these occasions, then he has forfeited his chance of introducing it. Note that pieces and pawns are allowed to move before the extra piece has been dropped. You are allowed to make a pawn-relocation if in check, if the pawn-relocation covers the check.