Avalanche chess

Avalanche chess is a chess variant designed by Ralph Betza in 1977. It is one of the more popular chess variants played in the world today. After moving one of your own pieces, you must move one of your opponent's pawns forward one space.

Rules are as normal chess except for the following:

1. After you move one of your own pieces, you must move one of your opponent's pieces one space forward toward you. You cannot use your opponent's pawn to capture and you cannot move your opponent's pawn two spaces forward.
2. If none of their opponent's pawns can be moved, then that part of the turn is forfeited.
3. If a player must move their opponent's pawn to promotion then the owner of the pawn chooses to what piece it promotes.
4. If after moving an opponent's pawn, that piece gives check, then their opponent wins the game immediately.