Simultaneous chess

How to play

Play as White. Make a plan, press Ready, and discover Black’s move.

Notation reference

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Make a plan

Choose a White piece and plan a move.

Your planChoose a White piece and plan a move.

You can change your plan before pressing Ready.

Reading the notation

Based on FIDE algebraic notation, extended for simultaneous play. FIDE algebraic notation

Planning records decisions. The result row appears only when something differs from the plan or adds a consequence. Read both rows together: a completed move or capture is not repeated. Results sit under the relevant player; mutual removals are centered.

K King · Q Queen · R Rook · B Bishop · N Knight. Pawns have no piece letter. Watch and mutual removal omit a non-pawn’s origin unless needed to identify it.

Familiar moves
Notation	Meaning
`e4`	Pawn moves to e4.
`Nf3`	Knight moves to f3.
`Bxe5`	Bishop captures on e5.
`dxe5`	Pawn from the d-file captures on e5.
`Nbd2`	The knight from the b-file moves to d2; another knight could also reach d2.
`O-O / O-O-O`	Kingside / queenside castling.
`e8=Q`	Pawn promotes to a queen on e8.

CrownDuet additions
Notation	Meaning
`B@e7 → Bxe7`	Planning: the bishop watches e7. Successful retaliation records only its capture, Bxe7; @ appears only in planning. Add an origin only when needed to identify the watcher.
`Q@b6 → Q~b6`	The queen’s Watch missed; the queen stayed on its original square. A failed Watch that moved or lost a piece also records that outcome.
`axb6 → a~b6`	The pawn reached b6, but its capture missed. If the pawn instead died in mutual contact, show mutual removal rather than a missed capture.
`e7@d8=Q`	Planning: the pawn on e7 watches d8, choosing a queen if it reaches d8 and survives. Results show promotion only when it happens.
`Q@e8`	Planning: the queen watches the King on e8. Success records only mutual removal of watcher and attacker; the King survives.
`Q~e8 / N~d4`	The declared King Watch or ordinary Watch did not trigger or failed to complete.
`N><B`	White’s knight and Black’s bishop are both removed. Their plans identify the route; no contact square is needed.
`c4><b5`	White’s pawn on c4 and Black’s pawn on b5 are both removed. Pawns keep their removal squares and omit P.
`+`	The King is in check after the round. The column identifies the affected player.
`#`	The player is checkmated after the round. The column identifies the affected player.
`#`	CrownDuet also uses # when the King is taken. The game-end reason distinguishes King capture from checkmate.
`hold`	Forced Hold: no move is available for this plan.

The ~ symbol means a planned interaction missed; the plan tells you whether it was a capture or a Watch. Mutual removal puts White on the left and Black on the right. Pawn squares show where they were removed; other pieces use origin file, rank, or square only when needed to distinguish them.