FORSYTH-EDWARDS NOTATION
The Scottish journalist and chess player, David Forsyth (1854-1909), created a simple system for describing chess positions. It was later extended by Steven J Edwards so that computers could use the notation to store more detailed information about a position.
Forsyth's system
- The position is described rank by rank starting with the eighth and ending with the first.
- Each rank is described from left to right.
- Pieces are indicated by a letter as follows: K=king, Q=queen, R=rook, B=bishop, N=Knight and P=pawn.
- Upper case letters denote a white piece and lower case letters a black piece.
- A number indicates 1 or more empty squares.
- Each rank is separated by a stroke (forward slash).
Examples of common positions
| DESCRIPTION | FORSYTH NOTATION |
|---|---|
| Starting position | rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR |
| Italian game | r1bqk1nr/pppp1ppp/2n5/2b1p3/2B1P3/5N2/PPPP1PPP/RNBQK2R |
| Mate for Black | 8/8/8/8/8/6k1/8/3q3K |
| Stalemate | 1k6/1P6/1K6/8/8/8/8/8 |
Edwards adaptations
Braille books and websites describing positions will often only use the notation as described above. The rest of the notation gives more specific information about the game and is normally used by computers.
There are six fields used in the full notation, each separated by a space.
1. Position
The previous section outlines how this works.
2. Player to move
A lower case "w" means White to move and a lower case "b" means Black to move.
3. Castling rights
A single hyphen means that neither player can castle. If this is not the case, a combination of four letters shows what castling rights both players have. The letters K and Q are used to show whether king-side or queen-side castling is possible. As with the position notation, upper case means white and lower case means black. Examples:
| - | Neither side can castle |
| KQkq | All castling is possible |
| Kk | Both sides can only castle short |
| kq | Black can castle either way |
| Qk | White can castle long and Black short |
4. En passant square
This field is used to show if a pawn has just moved forward two squares. If no such move has been made it shows a hyphen, otherwise it will show the square behind the pawn where a pawn would land if capturing en passant.
5. Half move clock
This number increases by one each time either player moves until a pawn is moved or a piece is captured at which point it is set to zero. It is used to determine if a 50 move draw can be claimed.
6. Move number
This shows the move number as written down in a score sheet. The first move of the game for both white and black is 1, the second is 2, the third is 3, and so on.