Disambiguation
Disambiguation is the extra letter or number added to a written move when two identical pieces can move to the same square, such as Nbd2 or R1e2, so the move reads only one way.
Also called: ambiguous move notation
Algebraic notation names the piece and the square it moves to. When two knights, rooks, bishops or queens can both reach that square, the notation needs a clue about which one is meant. The Laws give a short recipe. If the two pieces stand on different files, add the file letter of the piece that moves: with knights on g1 and e1, Ngf3 and Nef3 are different moves. If they share a file but stand on different ranks, add the rank number: with knights on g5 and g1, N5f3 and N1f3 are different. If they differ in both, the file letter is the preferred form. A capture keeps the same shape with an x inserted, as in Ngxf3. Only legal moves count, so a pinned piece that cannot go to the square does not create the ambiguity; on a scoresheet, though, adding the extra symbol anyway does no harm to a human reader. With three or more identical pieces, which can happen after promotions, both the file and rank may be needed. When you read your own scoresheet back later, precise disambiguation saves you from replaying the wrong game.
A neighboring idea is Annotation symbols. Annotation symbols are the short marks added to written moves, such as + for check, # for checkmate, x for a capture and (=) for a draw offer, along with commentators' marks like ! and ?.
Also worth reading is Long algebraic notation. Long algebraic notation is the fuller form of algebraic notation in which each move lists its square of departure as well as its square of arrival, so the knight move Nf3 becomes Ng1-f3 and the pawn move e4 becomes e2-e4.
Compare it with PGN. PGN is a text-file standard for chess games: header tags name the event, players and result, then the moves follow in algebraic notation, so databases, engines and websites can all import the same file.
Once "Disambiguation" is familiar, the next question is what to work on at your rating, which the improvement plans by rating band answer with game and puzzle data.
Related terms
Algebraic notation is the standard system for recording chess moves, naming each square by file letter and rank number and each move by the piece letter and destination square, as in Nf3 or exd5.
A scoresheet is the paper or electronic form on which each player writes down all the moves of the game in algebraic notation, and which both players sign or approve at the end to confirm the result.
PGN is a text-file standard for chess games: header tags name the event, players and result, then the moves follow in algebraic notation, so databases, engines and websites can all import the same file.
The knight moves to one of the nearest squares that is not on its own rank, file or diagonal, an L-shaped jump, and it is the only piece that can leap over other pieces.
The rook moves any number of squares along its rank or file, provided the path is clear, and it takes part in castling alongside the king.
Annotation symbols are the short marks added to written moves, such as + for check, # for checkmate, x for a capture and (=) for a draw offer, along with commentators' marks like ! and ?.
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
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Published rates for private, group and subscription chess coaching, with the source and the date of each.
A game review, a read on your level and a written study plan from George Li.
Sources
- FIDE Laws of Chess (effective 1 January 2023), Appendix C.10, read Oct 21, 2026.
- FIDE Laws of Chess (effective 1 January 2023), Appendix C.9, read Oct 21, 2026.
- FIDE Laws of Chess (effective 1 January 2023), Article 8.1, read Oct 21, 2026.
Want to spot this in your own games?
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