Avalanche Chess is a variant where each player moves their opponent's pawns.
Avalanche chess was created in the 1977 by chess variant designer Ralph Betza.
Avalanche chess is played like the standard game, with an additional rule: after a player has moved one of their pieces, they must move one of their opponent's pawns one square forward. If the opponent has no pawns left or the opponent's pawns have no legal moves, than that part of the turn is skipped.
Capturing with an opponent's pawn is not allowed, and a player cannot use a pawn advanced by the opponent to capture en passant.
A player may use either a normal move or an opponent pawn move to give check, and if a player is in check they must use their normal move to escape it. It is forbidden to place one's own king in check, even if there is an opponent pawn move that could block it.
If a pawn is advanced to the promotion rank, the owner of the pawn chooses the piece to promote to, regardless of who moved it there.
If a player moves an opponent's pawn to promotion, and the opponent chooses a piece that places the player's king in check, that is checkmate and the opponent wins the game.
If a player's only legal opponent pawn moves place their king in check, the opponent wins even if the player check(mated) their opponent's king on their turn.
This chess variant does not not have any notable sub-variants.