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Fischer Random Chess

Fischer Random Chess (also called Chess 960) is a chess variant created by Grandmaster Bobby Fischer (the 1972 World Champion of chess), originally announced on June 19, 1996 in Buenos Aires, Argentina. Fischer's goal was to create a chess variant in which chess creativity and talent would be more important than memorization and analysis of opening moves. His approach was to create a randomized initial chess position, which would thus make memorizing chess opening theory far less helpful.

The starting position for Fischer random chess must meet the following rules:

• White pawns are placed on their orthodox home squares.
• All remaining white pieces are placed on the first rank.
• The white king is placed somewhere between the two white rooks[?].
• The white bishops are placed on opposite-colored squares.
• The black pieces are placed equal-and-opposite the white pieces.

There are many procedures for creating this starting position. Hans L. Bodlaender has proposed the following procedure using one six-sided die to create an initial position; typically this is done just before the game commences:

• Roll the die, and place a white bishop on the black square indicated by the die, counting from the left. Thus 1 indicates the first black square from the left (a1 in algebraic notation), 2 indicates the second black square from the left (c1), 3 indicates the third (e1), and 4 indicates the fourth (g1). Since there are no fifth or sixth positions, re-roll 5 or 6 until another number shows.
• Roll the die, and place a white bishop on the white square indicated (1 indicates b1, 2 indicates d1, and so on). Re-roll 5 or 6.
• Roll the die, and place a queen on the first empty position indicated (always skipping filled positions). Thus, a 1 places the queen on the first (leftmost) empty position, while a 6 places the queen on the sixth (rightmost) empty position.
• Roll the die, and place a knight on the empty position indicated. Re-roll a 6.
• Roll the die, and place a knight on the empty position indicated. Re-roll a 5 or 6.
• Place a white rook on the 1st empty square of the first rank, the white king on the 2nd empty square of the first rank, and the remaining white rook on the 3rd empty square of the first rank.
• Place all white and black pawns on their usual squares, and place Black's pieces to exactly mirror White's (so Black should have on a8 exactly the same type of piece that White has on a1).

This procedure generates any of the 960 possible initial positions of Fischer Random Chess with an equal chance; on average, this particular procedure uses 6.7 die rolls. Note that one of these initial positions is the standard chess position, at which point a standard chess game begins.

It's also possible use this procedure to see why there are exactly 960 possible initial positions. Each bishop can take one of 4 positions, the Queen one of 6, and the two knights can have 5 or 4 possible positions, respectively. This means that there are 4*4*6*5*4 = 1920 possible positions if the two knights were different in some way. However, the two knights are indistinguishable during play; if they were swapped, there would be no difference. This means that the number of distinguishable positions is half of 1920, or 1920/2 = 960 possible distinguishable positions.

Once the pieces are set up, the rules for play are the same as standard chess. However, there are a few interpretations required for castling, because the standard rules presume specific locations of rook and king that are often untrue in Fischer Random Chess games.

When castling, the rook and king's final positions are exactly the same positions as they would be in standard chess. Thus, after a-side castling (notated as O-O-O and known as queen-side castling in orthodox chess), the King is on c (c1 for White and c8 for Black) and the Rook is on d (d1 for White and d8 for Black). After h-side castling (notated as O-O and known as king-side castling in orthodox chess), the King is on g and the Rook is on f. It is recommended that a player state "I am about to castle" before castling, to eliminate potential misunderstanding.

Castling may only occur under the following conditions, which are slight extensions of the standard rules for castling:

• The king and the castling rook must not have moved before in the game, including castling. Note that a player may castle at most once in a game.
• The king may not be in check before or after castling.
• The king may not move through any square (towards its destination) that is under attack. Although it is not entirely clear, this probably should be interpreted as including occupation of the square by an opposing piece.
• All squares between the king and rook, and their final squares, must not be occupied by any other pieces. Castling cannot capture pieces.

Castling in Fischer Random Chess can result in certain squares staying filled where they would have been empty in standard chess, depending upon the starting position and game play. For example, after a-side castling (O-O-O), it's possible for to have a, b, and/or e still filled, and after h-side castling (O-O), it's possible to have e and/or h filled.

Early definitions of the Fischer Random Chess castling rules were unfortunately imprecise. Another chess variant, FullChess, is set up just like Fischer Random Chess but with subtlely different castling rules. It easier to describe how their castling rules are identical: both variants require that the king and rook involved in castling be unmoved, both demand that the end positions of king and rook be the same as in a traditional chess game, and both require that none of the squares from the king's starting square to his target square (including starting and ending positions) are under attack.

However, FullChess has a slightly different rule involving occupied squares: "Castling is permitted only, when nothing is standing from the king to his target square (incl.) except an involved rook, and when nothing is standing from the rook to its target square (incl.) except an involved king (from that it can be concluded, that all the squares must be free between both figures)." Early Fischer Random Chess rules were unclear about whether or not the back row needed to be clear, so the FullChess rules were one way to remove the imprecision. Later versions of the Fischer Random Chess rules clarified that indeed, Fischer intended to allow castling to "jump" other pieces.

If the initial placement happens to be the traditional initial placement, these castling rules have an identical effect. However, in some situations the different rules produce different results. In particular, Fischer Random Chess allows a rook to "hop" over other pieces on the back row when castling while FullChess rules do not.

Examining openings for Fischer Random Chess is in its infancy, but opening fundamentals still apply. These include: protect the King, control the center squares (directly or indirectly), and develop your pieces rapidly starting with the less valuable pieces. Some starting positions have unprotected pawns that may need to be dealt with quickly.

It is often argued that two games should be played with each initial position, with players alternating as white and black, since some initial positions may turn out to give white a much bigger advantage than standard chess.

Since the initial position is usually not the orthodox chess initial position, recorded games must also record the initial position. Games recorded using the Portable Game Notation (PGN) can record the initial position using Forsyth-Edwards Notation (FEN), as the value of the "FEN" tag. Note that not all chess programs can handle castling correctly in Fischer Random Chess games.

The first Fischer Random Chess tourney was held in Yugoslavia in the spring of 1996, and was won by Grandmaster Peter Leko[?].

In 2001, Leko became the first Fischer Random Chess world champion, defeating Grandmaster Michael Adams[?]. There were no qualifying matches (also true of the first orthodox world chess champion titleholders), but both players were in the top five in the January 2001 world rankings for orthodox chess. Leko was chosen because of the many novelties he has introduced to known chess theories, as well as his previous tourney win; in addition, Leko has played Fischer Random Chess games with Fischer himself. Adams was chosen because he is the world champion in blitz (rapid) chess and is regarded as an extremely strong player in unfamiliar positions. The match was won by a narrow margin, 4.5 to 3.5.

In 2002, Yugoslavian Grandmaster Svetozar Gligoric[?] published the book Shall We Play Fischerandom Chess?, popularizing this variation further.

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