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Ponderchess / Glossary

Algebraic notation in chess

Algebraic notation is the standard way to write chess moves. Each square is named by its file, a to h, and its rank, 1 to 8, and a move is written as a piece letter followed by the destination square, so Nf3 means a knight moves to f3.

This position arises after 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.c3 Nf6 5.d4 exd4 6.cxd4 Bb4+. Pawn moves name only the square (e4), piece moves add a capital letter (Nf3), x marks a capture, a pawn capture names the pawn's file (exd4, cxd4) and + marks check. White now plays Bd2, and after Bxd2+ both white knights can capture on d2, so the knight recapture is written Nbxd2 to show that the b1-knight takes.7.Bd2 Bxd2+ 8.Nbxd2

Squares and pieces

Seen from White's side, the files are lettered a to h from left to right and the ranks numbered 1 to 8 from White's end to Black's. Every square has one fixed name, whoever is looking: a1 is the corner square on White's left, White's king starts on e1 and Black's on e8.

The pieces are K for king, Q for queen, R for rook, B for bishop and N for knight, since K is already taken. Pawns have no letter. Books in other languages use their own piece letters, but the squares are named the same way.

Writing moves

A pawn move gives only the destination square: e4. A piece move adds its letter: Nf3, Bb5. A capture uses x: Bxc6. A pawn capture names the file the pawn came from, so exd5 means the e-pawn captures on d5.

Check is marked +, and checkmate #. Kingside castling is O-O and queenside castling O-O-O. Promotion is written with the new piece after an equals sign, as in e8=Q. Moves are numbered in pairs, 1.e4 e5 2.Nf3 Nc6, and a Black move written on its own takes three dots, as in 2...Nc6.

When two pieces can reach the same square

If two identical pieces could move to the same square, add the file they start from, or the rank if they share a file. With knights on b1 and f3 both able to go to d2, Nbd2 means the b1-knight moves. With rooks on e1 and e5, R1e3 means the rook on e1 goes to e3.

Annotators add symbols after moves: ! for a good move, !! for a brilliant one, ? for a mistake, ?? for a blunder, !? for an interesting move and ?! for a dubious one. They are comments, not part of the move itself.

Common mistakes

  • Leaving out the starting file of a pawn capture, writing xd5 instead of exd5.
  • Naming squares from Black's side of the board. The names are fixed from White's side for both players.
  • Writing an ambiguous move such as Nd2 when two knights can reach d2.

Questions about algebraic notation

What does x mean in chess notation?

A capture. Bxe5 means a bishop captures whatever stands on e5.

How is castling written?

O-O for kingside castling and O-O-O for queenside castling.

What does Nbd2 mean?

The knight on the b-file moves to d2. The b is added because another knight could also have gone to d2.