Fischer random chess · FIDE Laws, Guidelines II
Chess960 position generator
Choose a number from 0 to 959, or roll a random one, for the start position with a board diagram, its FEN and how castling works from it. No. 518 is the standard chess position.
Chess960 start position
No. 518
RaNbBcQdKeBfNgRh
No. 518 is the standard chess position.
- FEN (X-FEN)
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1- Shredder-FEN
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w HAha - 0 1
Castling from this position
- 0-0 (g-side): king e1 to g1, rook h1 to f1. Double-move castling: the king and the rook both move. Squares f1 and g1 must be empty apart from the castling king and rook.
- 0-0-0 (c-side): king e1 to c1, rook a1 to d1. Double-move castling: the king and the rook both move. Squares b1, c1 and d1 must be empty apart from the castling king and rook.
Black castles the same way on the eighth rank. After castling the king and rook stand where they would in standard chess (FIDE Laws, Guidelines II.3).
The rules of the start position
Under the FIDE Laws of Chess (Guidelines II), the white pawns stand on the second rank as usual and the other white pieces are placed at random on the first rank, with the king somewhere between the two rooks and the bishops on squares of opposite colours. Black’s pieces mirror White’s. A computer, dice, coins or cards can choose the position. That gives exactly 960 positions.
Castling
Each player may castle once, towards the c-file (0-0-0) or the g-file (0-0). Afterwards the king and rook stand exactly where they would in standard chess: king c1 and rook d1, or king g1 and rook f1. Every square the king and rook cross or land on must be empty apart from those two pieces, and in some positions only one of them moves. The tool spells out each case.
The numbers 0 to 959
The numbering devised by Reinhard Scharnagl is the standard one: divide the number by 4 for the light-squared bishop (b, d, f or h), by 4 again for the dark-squared bishop (a, c, e or g), by 6 for the queen’s square among those left, then use the last digit, 0 to 9, for the two knights; the rooks and king fill the last three squares. All 960 positions here are checked against Mark Weeks’ published list.
Is “Freestyle chess” the same game?
Yes. FIDE says Freestyle Chess is also known as Chess960 or FIDE Fischer Random Chess. The first FIDE Freestyle Chess World Championship, run with Freestyle Chess Operations GmbH, was played in Weissenhaus, Germany, on 13–15 February 2026.
Sources
- Start-position rules and castling: FIDE Laws of Chess, taking effect from 1 January 2023, Guidelines II (II.2, II.3).
- Numbering scheme: Wikipedia, Fischer random chess numbering scheme (used because FIDE publishes no numbering); positions tested against Mark Weeks, Chess960 start positions.
- The Freestyle name: FIDE, “The first official FIDE Freestyle Chess World Championship to be hosted in Weissenhaus” (7 January 2026).
Questions
Which Chess960 number is the normal starting position?
No. 518, RNBQKBNR. Position 0 is BBQNNRKR and position 959 is RKRNNQBB.
How is the FEN written for Chess960?
In a start position each side has one rook on each side of the king, so the usual KQkq works (X-FEN). Shredder-FEN names the rooks’ files instead, such as HAha for the standard position.
Can you castle on the first move in Chess960?
In some positions, yes: the FIDE Laws note that castling can come as early as the first move when the squares it needs are already empty.