1One pawn is a queen
Before the game starts you pick one of your eight pawns in secret. Your opponent does the same. Neither of you sees the other's choice.
The rule
Each player secretly picks one of their pawns that is really a queen, and can reveal it later by moving it as one.
How it plays
2Using it reveals it
The first time you move that pawn like a queen, everyone sees what it was. Until then it walks, blocks and captures like any other pawn.
3Timing is the whole game
Spend it early and you win a piece. Hold it and your opponent plays a whole game against something they cannot see. Both are correct. Neither is safe.
4The exact rules
Before the game each player picks one of their own pawns in secret. It is a pawn in every way until it is revealed: it can be captured as one and taken en passant, and it gives no check while it is hidden. Reveal it on your turn and it moves as a queen that same turn, and it is a queen for the rest of the game. Checkmate the other king, as in ordinary chess. The hidden queen is only the surprise that helps you do it.
Six finds
Moments to look out for. Each one you make in a game is kept in your finds.
Late reveal
Reveal your queen on your 20th move or later.
Reveal with check
Reveal your queen and give check.
Reveal by capture
Reveal your queen by capturing a piece.
Reveal mate
Reveal your queen with a move that checkmates.
Kept it hidden
Win by checkmate without ever revealing your queen.
Won after revealing
Win by checkmate after revealing your queen.
Questions
Do I need an account?
No. An account keeps your rating and your finds on every device.