Quantum Chess

Your turn (White)

Taken White 0 · Black 0

Specials: knight tandem, king/rook pawn push, rook/king pawn shove, quiver e.p., countercheck. New game or press R to reset.

Moves

No moves yet.

Variant rules

Base. FIDE chess. You are White vs Stockfish. No clocks. Kings are never captured.
Tandem. Knight orthogonally beside a quiver or the king: click knight, then the linked piece, then L. That piece lands on the elbow (captures there; friendly elbow is illegal). One move only. The knight can still move alone. The king cannot tandem onto a checked square.
File push. King or rook directly behind its pawn shoves it 1 square (or 2 from the pawn’s start rank). Both move forward together. Enemy pieces ahead are captured; friendly pieces block. Promotes on the last rank. The king cannot push onto check. A king may not double-push if a quiver could en passant onto the passed square (the king would land there). Rook double-pushes are still allowed.
Rank shove. King or rook only shoves pawns on the side it is pushing — pawns on the other side stay. One square. Connected pawns in that direction all shift. The far pawn may capture; friendly pieces block. The king cannot shove onto check.
Quiver e.p. After a pawn double-steps (including a rook file-push), a quiver on any clear diagonal to the passed square lands there and takes the jumper. Click the next square on that diagonal to land there instead and take that piece too (Ba3 vs d7–d5: click d6 or e7). If a shoving rook sits on the passed square, the rook is taken too. A king double-push onto that square is illegal. Added to normal pawn en passant. Cannot take a king.
Countercheck. When in check you may stay in check once if you also check the other king. After that, the sequence must be resolved. If neither side can escape, it is a draw. Walking the king into check is never allowed. Resets when neither king is in check.
Reset. New game, or on a keyboard press R to restart.