When your move forces the opponent's pawn to reach your back rank (via Superpermutation), that pawn is automatically promoted to a queen by default, even if this outcome is unfavorable to both players.
Example Position 1:
Black rolls a 2 (g-file) and plays Rf8-g8:
White pawn promotes to a queen automatically.
Illegal Move Rule:
If forced promotion results in a check to the moving player’s own king, the move is illegal.
Example Position 2:
Black rolls a 2 (g-file).
Illegal moves:
Nh6-g8 (promotes White pawn to queen, delivering check to Black king)
Rh8-g8 (same result)
Both moves result in self-check after forced promotion, making them invalid.
