2 | You can forbid the opponent to play the move he wanted.
5 All rules are as in normal chess, except for the following: each turn,
6 a player has the right to refuse at most one move of the opponent.
7 To refuse a move, re-play it from end to starting square.
10 Two moves promoting the same pawn on the same square, but to a
11 different type of piece, count as two different moves.
13 p If a player has only one legal move, this move must be accepted.
19 a(href="https://www.chessvariants.com/other.dir/refusal.html")
23 p Inventor: Fred Galvin (1958)