Rules of Fischerrandom Chess

F.1

Before a Chess960 game a starting position is randomly set up, subject to certain rules. After this, the game is played in the same way as standard chess. In particular, pieces and pawns have their normal moves, and each player's objective is to checkmate the opponent's king.

F.2

Starting position requirements

The starting position for Chess960 must meet certain rules. White pawns are placed on the second rank as in regular chess. All remaining white pieces are placed randomly on the first rank, but with the following restrictions:

1. the king is placed somewhere between the two rooks, and
2. the bishops are placed on opposite-colored squares, and
3. the black pieces are placed equal-and-opposite to the white pieces.

The starting position can be generated before the game either by a computer program or using dice, coin, cards, etc.

F.3

Chess960 Castling Rules

a.

Chess960 allows each player to castle once per game, a move by potentially both the king and rook in a single move. However, a few interpretations of standard chess games rules are needed for castling, because the standard rules presume initial locations of the rook and king that are often not applicable in Chess960.

b.

How to castle

In Chess960, depending on the pre-castling position on the castling king and rook, the castling manoeuvre is performed by one of these four methods:

1. double-move castling: by on one turn making a move with the king and a move with the rook, or
2. transposition castling: by transposing the position of the king and the rook, or
3. king-move-only castling: by making only a move with the king, or
4. rook-move-only castling: by making only a move with the rook.

Recommendation

1. When castling on a physical board with a human player, it is recommended that the king be moved outside the playing surface next to his final position, the rook then be moved from its starting to ending position, and then the king be placed on his final square.
2. After castling, the rook and king's final positions are exactly the same positions as they would be in standard chess.

Clarification

Thus, after c-side castling (notated as O-O-O and known as queen-side castling in orthodox chess), the King is on the c-square (c1 for White and c8 for Black) and the Rook is on the d-square (d1 for White and d8 for Black). After g-side castling (notated as O-O and known as king-side castling in orthodox chess), the King is on the g-square (g1 for White and g8 for Black) and the Rook is on the f-square (f1 for White and f8 for Black).

Notes

1. To avoid any misunderstanding, it may be useful to state "I am about to castle" before castling.
2. In some starting positions, the king or rook (but not both) do not move during castling.
3. In some starting positions, castling can take place as early as the first move.
4. ll the squares between the king's initial and final squares (including the final square), and all of the squares between the rook's initial and final squares (including the final square), must be vacant except for the king and castling rook.
5. In some starting positions, some squares can stay filled during castling that would have to be vacant in standard chess. For example, after c-side castling (O-O-O), it's possible for to have a, b, and/or e still filled, and after g-side castling (O-O), it's possible to have e and/or h filled.

1.

a.

If a game is not finished at the end of the time prescribed for play, the arbiter shall require the player having the move to ‘seal’ that move. The player must write his move in unambiguous notation on his scoresheet, put his scoresheet and that of his opponent in an envelope, seal the envelope and only then stop his clock without starting his opponent's clock. Until he has stopped the clocks, the player retains the right to change his sealed move. If, after being told by the arbiter to seal his move, the player makes a move on the chessboard he must write that same move on his scoresheet as his sealed move.

b.

A player having the move, who adjourns the game before the end of the playing session, shall be considered to have sealed at the nominal time for the end of the session, and his remaining time shall so be recorded.

2.

The following shall be indicated upon the envelope:

a.

the names of the players, and

b.

the position immediately before the sealed move, and

c.

the time used by each player, and

d.

the name of the player who has sealed the move, and

e.

the number of the sealed move, and

f.

the offer of a draw, if the proposal is current, and

g.

the date, time and venue of resumption of play.

3.

The arbiter shallcheck the accuracy of the information on the envelope and is responsible for the safe-keeping of it.

4.

If a player proposes a draw after his opponent has sealed his move, the offer is valid until the opponent has accepted it or rejected it as in Article 9.1.

5.

Before the game is to be resumed, the position immediately before the sealed move shall be set up on the chessboard, and the times used by each player when the game was adjourned shall be indicated on the clocks.

6.

If prior to the resumption the game is agreed drawn, or if one of the players notifies the arbiter that he resigns, the game is concluded.

7.

The envelope shall be opened only when the player who must reply to the sealed move is present.

8.

Except in the cases mentioned in the Articles 5, 6.9 and 9.6, the game is lost by a player whose recording of his sealed move:

a.

is ambiguous, or

b.

is recorded such that its true significance is impossible to establish, or

c.

is illegal.

9.

If, at the agreed resumption time:

a.

the player having to reply to the sealed move is present, the envelope is opened, the sealed move made on the chessboard and his clock started.

b.

the player having to reply to the sealed move is not present, his clock shall be started. On his arrival, he may stop his clock and summon the arbiter. The envelope is then opened and the sealed move made on the chessboard. His clock is then restarted.

c.

the player who sealed the move is not present, his opponent has the right to record his reply on the scoresheet, seal his scoresheet in a fresh envelope, stop his clock and start the absent player’s clock instead of making his reply in the normal manner. If so, the envelope shall be handed to the arbiter for safe-keeping and opened on the absent player’s arrival.

10.

The player shall lose the game if he arrives at the chessboard more than one hour late for the resumption of an adjourned game (unless the rules of the competition specify or the arbiter decides otherwise).
However, if the player who made the sealed move is the late player, the game is decided otherwise, if:

a.

the absent player has won the game by virtue of the fact that the sealed move is checkmate, or

b.

the absent player has produced a drawn game by virtue of the fact that the sealed move is stalemate, or a position as described in Article 9.6 has arisen on the chessboard, or

c.

the player present at the chessboard has lost the game according to Article 6.9.

11.

a.

If the envelope containing the sealed move is missing, the game shall continue from the position, with the clock times recorded at the time of adjournment. If the time used by each player cannot be re-established the arbiter shall set the clocks. The player who sealed the move makes the move he states he sealed on the chessboard.

b.

If it is impossible to re-establish the position, the game is annulled and a new game must be played.

12.

If, upon resumption of the game, either player points out before making his first move that the time used has been incorrectly indicated on either clock, the error must be corrected. If the error is not then established the game continues without correction unless the arbiter feels that the consequences will be too severe.

13.

The duration of each resumption session shall be controlled by the arbiter’s timepiece. The starting time and finishing time shall be announced in advance.