Apocalypse Rules

Both players play a move "at the same time". The goal is to eliminate all enemy pawns.

This variant is inspired by the Four Horsemen of the Apocalypse mythology. Knights are horsemen, and pawns are footmen. If all footmen of one color die, the other side wins.

At each turn you can decide either to play safely an apparently valid move, or speculate on your opponent's move and choose a move valid only conditionally on his choice. In this last case the move may end up not being playable: you would get a penalty point. Two penalty points loses the game. For example in the initial position, 1.(c1)c2 is safe while 1.axb3 will be valid only if black plays 1...Nb3.

Resolving rules:

• If both moves are illegal none are played. If one is illegal, the other is played.
• If a capture is intended but the target moved, the move is still played without capturing anything.
• If both moves arrive on the same square: the illegal move prevails (if any), so the other piece vanishes (higher risk is rewarded). If both moves are legal, then a horseman wins over a footman, whereas two pieces of the same nature disappear.

Promotions

Pawns automatically promote in a knight, except if the player already have two horsemen on the board. In this case the footman is relocated on any free square which is not on last rank. Even in this last case, pawn promotions may appear possible by anticipation of a knight capture. This is risky but playable.

End of the game

As stated previously, losing all pawns lose the game, so promoting your last pawn loses. It may be the only legal move. If however both footmen armies vanish at the same time, it's a draw. It can happen if the two last pawns decide to advance to the same square for example. Finally, if both sides get the second penalty point at the same time it's also a draw.

Resources

Apocalypse chess on chessvariants.com. This variant is playable at apocalypsechess.online without the promotion restriction.