One of 960 possible starting positions
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| Years active | Since June 1996 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Genre(s) | Board game | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Players | 2 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Setup time | About 1 minute; an additional minute to determine starting position | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Playing time | Casual games usually last 10 to 60 minutes; tournament games last anywhere from about ten minutes (blitz chess) to six hours or longer. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Random chance | None | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Skill(s) required | Tactics, strategy | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Chess960 (or Fischer Random Chess) is a chess variant invented and advocated by former World Chess Champion Bobby Fischer, originally announced on June 19, 1996 in Buenos Aires, Argentina. It employs the same board and pieces as standard chess, but the starting position of the pieces is randomized along the players' home ranks. The random setup (if not the standard starting position) makes the possibility of obtaining an advantage through the memorization of opening moves impracticable, forcing players to rely instead on talent and creativity.
Randomizing the main pieces has long been known as Shuffle Chess, but Chess960 introduces new rules so that full castling options are retained in all starting positions, resulting in 960 unique positions. To maintain the character of standard chess, a player's bishops must start on opposite-color squares, and the king must start on a square between the rooks.
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| This article uses algebraic notation to describe chess moves. |
Before the game, a starting position is randomly determined and set up, subject to certain requirements. After setup, the game is played in the same way as standard chess (except for castling from the different possible starting positions for king and rooks). In particular, pieces and pawns have their normal moves, and the objective (checkmate) is the same.
White pawns are placed on the second rank as in standard chess. All remaining white pieces are placed randomly on the first rank, with the following restrictions:
Black's pieces are placed equal-and-opposite to White's pieces. For example, if the white king is randomly determined to start on f1, then the black king is placed on f8. (Note that the king never starts on the a- or h-files, since this would leave no space for a rook.)
The starting position can be generated before the game by computer program, or chosen by the players by a variety of methods using dice, coin, cards, etc.
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There are many procedures for selecting a starting position. A common one is that proposed by Ingo Althoefer in 1998, which requires only one six-sided die:
This leaves three empty squares. Place the king on the middle empty square, and the rooks on the remaining two squares. 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 the same type of piece White has on a1, except that bishops would be on opposite-color squares).
This particular procedure generates any of the 960 possible initial positions with equal chance. It uses an average of 6.7 die rolls. Note that one of these initial positions (rolled by 2-3-3-2-3 or 2-3-3-4-2) is the standard chess position, at which point a standard chess game ensues.
This procedure can be used to understand why there are exactly 960 possible initial positions. Each bishop can take one of four positions, the queen one of six, and the two knights can assume five or four possible positions respectively. This leaves three open squares which the king and rooks must occupy according to setup stipulations, without choice. This means there are 4×4×6×5×4 = 1920 possible starting positions if the two knights were different in some way. However, the two knights are indistinguishable during play (if swapped, there would be no difference), so the number of distinguishable possible positions is half of 1920, or 1920/2 = 960. (Half of the 960 are left-right mirror images of the other half, however Chess960 castling rules preserve left-right asymmetry in play.)
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Like standard chess, Chess960 allows each player to castle once per game, moving both the king and a rook in a single move. However, the castling rules were reinterpreted in Chess960 to support the different possible initial positions of the king and rook.
After castling, the king and rook's final positions are exactly the same as they would be in standard chess. Thus, after a-side castling (also called sometimes c-castling), the king is on the c-file (c1 for White and c8 for Black) and the a-side rook is on the d-file (d1 for White and d8 for Black). This move is notated as 0-0-0 and is known as queenside castling in orthodox chess. After h-side castling (also called sometimes g-castling), the king is on the g-file and the h-side rook is on the f-file. This move is notated as 0-0 and is known as kingside castling in orthodox chess. It is recommended that a player state "I am about to castle" before castling, to avoid potential misinterpretation.
However, castling may only occur under the conditions listed below. The first two are identical to the standard chess castling rules. The third is an extension of the standard chess rule, which requires only that the squares between the king and castling rook are vacant.
If the initial position happens to be the standard chess initial position, the Chess960 castling rules have exactly the same result as the standard chess castling rules. In some starting positions, some squares can remain occupied during castling that would have to be vacant in standard chess. For example, after a-side castling (0-0-0), it is possible that a, b, and/or e are still filled; and after h-side castling (0-0), it is possible that e and/or h are filled. In some starting positions, the king or rook (but not both) do not move during castling.
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. This is always unambiguous, and is a simple rule to follow.
Eric van Reem suggests other ways to castle:
In the meantime there has been an adjustment setting of the World New Chess Association (WNCA) that when performing a castling move it is irrelevant in which sequence involved pieces were touched. All pieces involved in a move may be touched arbitrarily. When castling those pieces are the king and rook, and in capturing moves they are the capturing and the captured piece. Especially with players new to Chess960 it might make sense also to announce a castling to avoid misunderstandings. When a chess clock will be used, pressing the button could be taken as a sign that a castling move has been completed.
When castling using a computer interface, programs should have separate a-side (0-0-0) and h-side (0-0) castling actions (e.g., as a button or menu item). Ideally, programs should also be able to detect a king or rook move that cannot be anything other than a castling move and consider that a castling move. Recommended gestures are: the king is moving to his at least two steps distant castling target square or else upon the involved rook, to avoid by this a possible confusion with normal king's moves.
When using an electronic board, to castle one should remove the king, remove the castling rook, place the castling rook on its new position, and then place the king on its new position. This will create an unambiguous move for electronic boards, which often only have sensors that can detect the presence or absence of an object on each square (and cannot tell what object is on the square). Ideally, electronic boards should detect a king or rook move that can only be a castling move as well, but users should not count on this.
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The study of openings in Chess960 is in its infancy, but fundamental opening principles still apply, including: protect the king, control the central squares (directly or indirectly), and develop rapidly starting with the less valuable pieces. Some starting positions have unprotected pawns that may need to be dealt with quickly.
It has been argued that two games should be played from each starting position, with players alternating as White and Black, since some initial positions may offer White a bigger advantage than in standard chess. For example, in some Chess960 starting positions White can attack an unprotected black pawn after the first move, whereas in standard chess it takes two turns for White to attack and there are no unprotected pawns. (See first-move advantage in 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. Castling is notated the same as in standard chess (except PGN requires letter O not number 0). Note that not all chess programs can handle castling correctly in Chess960 games (except if the initial position is the standard chess initial position). To correctly record a Chess960 game in PGN, an additional "Variant" tag (not "Variation" tag, which has a different meaning) must be used to identify the rules; the rule named "Fischerandom" is accepted by many chess programs as identifying Chess960, though "Chess960" should be accepted as well. This means that in a PGN-recorded game, one of the PGN tags (after the initial seven tags) would look like this: [Variant "Fischerandom"].
FEN is capable of expressing all possible starting positions of Chess960. However, unmodified FEN cannot express all possible positions of a Chess960 game. In a game, a rook may move into the back row on the same side of the king as the other rook, or pawn(s) may be underpromoted into rook(s) and moved into the back row. If a rook is unmoved and can still castle, yet there is more than one rook on that side, FEN notation as traditionally interpreted is ambiguous. This is because FEN records that castling is possible on that side, but not which rook is still allowed to castle.
A modification of FEN, X-FEN, has been devised by Reinhard Scharnagl to remove this ambiguity. In X-FEN, the castling markings "KQkq" have their expected meanings: "Q" and "q" mean a-side castling is still legal (for White and Black respectively), and "K" and "k" mean h-side castling is still legal (for White and Black respectively). However, if there is more than one rook on the baseline on the same side of the king, and the rook that can castle is not the outermost rook on that side, then the file letter (uppercase for White) of the rook that can castle is used instead of "K", "k", "Q", or "q"; in X-FEN notation, castling potentials belong to the outermost rooks by default. The maximum length of the castling value is still four characters. X-FEN is upwardly compatible with FEN, that is, a program supporting X-FEN will automatically use the normal FEN codes for a traditional chess starting position without requiring any special programming. As a benefit all 18 pseudo FRC positions (positions with traditional placements of rooks and king) still remain uniquely encoded.
The solution implemented by chess engines like Shredder and Fritz is to use the letters of the columns on which the rooks began the game. This scheme is sometimes called Shredder-FEN. For the traditional setup, Shredder-FEN would use HAha instead of KQkq.
Fischer Random Chess is a variant of Shuffle chess defined by former World Champion Bobby Fischer and introduced formally to the chess public on June 19, 1996, in Buenos Aires, Argentina. Shuffle Chess had been played for quite some time before this, as early as 1842.[1] Fischer's goal was to eliminate what he considered the complete dominance of openings preparation in chess today, and to replace it with creativity and talent. His belief about Russians fixing all international games also provided motivation. In a situation where the starting position was random it would be impossible to fix every move of the game. Since the opening book for each possible opening position would be too difficult to devote to memory (960 "book opening" systems), each player must create every move originally. From the first move, both players have to come up with original strategies and cannot use well-known thinking patterns. Fischer believed that eliminating memorized book moves would level the playing field.
The first Fischer Random Chess tournament was held in Yugoslavia in the spring of 1996, and was won by Grandmaster Péter Lékó.
In 2010 the US Chess Federation sponsored its first Chess960 tournament, at the Jerry Hanken Memorial US Open tournament in Irvine, California. This one-day event, directed by Damian Nash, saw a first place tie between GM Larry Kaufmann and FM Mark Duckworth.[2]
In 2005, The Baron played two Chess960 games against Chess960 World Champion Peter Svidler; Svidler won 1½–½. The chess program Shredder, developed by Stefan Meyer-Kahlen from Düsseldorf, Germany, played two games against Zoltán Almási from Hungary; Shredder won 2–0.
In 2001, Lékó became the first Fischer Random Chess world champion, defeating GM Michael Adams in an eight-game match played as part of the Mainz Chess Classic. 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. Lékó was chosen because of the many novelties he has introduced to known chess theories, as well as his previous tournament win; in addition, Lékó has supposedly played Fischer Random Chess games with Fischer himself. Adams was chosen because he was the world number one in blitz (rapid) chess and is regarded as an extremely strong player in unfamiliar positions. The match was won by a narrow margin, 4½ to 3½.[3]
In 2002 at Mainz, an open tournament was held which attracted 131 players. Peter Svidler won the event. Other interesting events happened in 2002. The website ChessVariants.org selected Fischer Random chess as its "Recognized Variant of the Month" for April 2002. Yugoslavian Grandmaster Svetozar Gligorić published in 2002 the book Shall We Play Fischerandom Chess?, popularizing this variant further.
At the 2003 Mainz Chess Classic, Svidler beat Lékó in an eight game match for the World Championship title by a score of 4½-3½. The Chess960 open tournament attracted 179 players, including 50 GMs. It was won by Levon Aronian, the 2002 World Junior Champion. Svidler is the official first World New Chess Association (WNCA) world champion inaugurated on August 14, 2003 with Jens Beutel, Mayor of Mainz as the President and Hans-Walter Schmitt, Chess Classic organiser as Secretary.[4][5] The WNCA maintains an own dedicated Chess960 rating list.[6]
Aronian played Svidler for the title at the 2004 Mainz Chess Classic, losing 4½–3½. At the same tournament in 2004, Aronian played two Chess960 games against the Dutch computer chess program The Baron, developed by Richard Pijl. Both games ended in a draw. It was the first ever man against machine match in Chess960. Zoltán Almási won the Chess960 open tournament in 2004.
Almási and Svidler played an eight-game match at the 2005 Mainz Chess Classic. Once again, Svidler defended his title, winning 5–3. Levon Aronian won the Chess960 open tournament in 2005. During the Chess Classic 2005 in Mainz, initiated by Mark Vogelgesang and Eric van Reem, the first-ever Chess960 computer chess world championship was played.[7] Nineteen programs, including the powerful Shredder, played in this tournament. As a result of this tournament, Spike became the first Chess960 computer world champion.
The 2006 Mainz Chess Classic saw Svidler defending his championship in a rematch against Levon Aronian. This time, Aronian won the match 5–3 to become the third ever Fischer Random Chess World Champion. Étienne Bacrot won the Chess960 open tournament, earning him a title match against Aronian in 2007. In 2006 Shredder won the computer championship, making it Chess960 computer world champion. Three new Chess960 world championship matches were held, in the women, junior and senior categories. In the women category, Alexandra Kosteniuk became the first Chess960 Women World Champion by beating Elisabeth Paehtz 5½ to 2½. The 2006 Senior Chess960 World Champion was Vlastimil Hort, and the 2006 Junior Chess960 World Champion was Pentala Harikrishna.
In 2007 Mainz Chess Classic Aronian successfully defended his title of Chess960 World Champion over Viswanathan Anand, while Victor Bologan won the Chess960 open tournament. Rybka won the 2007 computer championship.
The last Mainz tournament was held in 2009.[8]
| Year | World Chess960 Championship | Mainz Open | World Chess960 Women's Championship | Computer Championship |
|---|---|---|---|---|
| 2001 | Péter Lékó (4½–3½ vs Michael Adams) | - | - | - |
| 2002 | - | Peter Svidler | - | - |
| 2003 | Peter Svidler (4½–3½ vs Péter Lékó) | Levon Aronian | - | - |
| 2004 | Peter Svidler (4½–3½ vs Levon Aronian) | Zoltán Almási | - | - |
| 2005 | Peter Svidler (5–3 vs Zoltán Almási) | Levon Aronian | - | Spike |
| 2006 | Levon Aronian (5–3 vs Peter Svidler) | Étienne Bacrot | Alexandra Kosteniuk (5½–2½ vs Elisabeth Pähtz) | Shredder |
| 2007 | Levon Aronian (2–2, 1½–½ vs Viswanathan Anand) | Victor Bologan | - | Rybka |
| 2008 | - | Hikaru Nakamura | Alexandra Kosteniuk (2½–1½ vs Kateryna Lahno) | Rybka |
| 2009 | Hikaru Nakamura (3½–½ vs Levon Aronian) | Alexander Grischuk | - | Rybka |
This chess variant has held a number of different names. It was initially known as "Fischerandom Chess" after Fischer formalized his variation of Shuffle Chess. Later name forms included "Fischer Random Chess", "FR Chess", and "FRC".
Hans-Walter Schmitt, chairman of the Frankfurt Chess Tigers e.V. and an advocate of this variant, started a brainstorming process for selecting a new name, which had to meet requirements of leading grandmasters; specifically, the new name and its parts:
The effort culminated in the name choice Chess960 – derived from the number of different possible starting positions.
R. Scharnagl, another proponent of the variant, advocated the term "FullChess" instead. But today he uses FullChess to refer to variants which consistently embed traditional chess (e.g. Chess960, and some new variants based on the extended 10×8 piece set in Capablanca chess). He currently recommends the name Chess960 in preference to Fischer Random Chess for the variant.
Bobby Fischer never publicly stated his feeling about the name 'Chess960'.
The initial setup need not necessarily be random. The players or a tournament setting may decide on a specific position in advance, for example. Tournament Directors prefer that all boards in a single round play the same random position, as to maintain order and abbreviate the setup time for each round.
Edward Northam suggests the following approach for allowing players to jointly create a position without randomizing tools: First, the back ranks are cleared of pieces, and the white bishops, knights, and queen are gathered together. Starting with Black, the players, in turn, place one of these pieces on White's back rank, where it must stay. The only restriction is that the bishops must go on opposite colored squares. There will be a vacant square of the required color for the second bishop, no matter where the previous pieces have been placed. Some variety could be introduced into this process by allowing each player to exercise a one time option of moving a piece already on the board instead of putting a new piece on the board. After all five pieces have been put on the board, the king must be placed on the middle of the three vacant back rank squares that remain. Rooks go on the other two.
This approach to the opening setup has much in common with Pre-Chess, the variant in which White and Black, alternately and independently, fill in their respective back ranks. Pre-Chess could be played with the additional requirement of ending up with a legal Chess960 opening position. A chess clock could even be used during this phase as well as during normal play.
Without some limitation on which pieces go on the board first, it is possible to reach impasse positions, which cannot be completed to legal Chess960 starting positions. Example: Q.RB.N.N If the players want to work with all eight pieces, they must have a prior agreement about how to correct illegal opening positions that may arise. If the bishops end up on same color squares, a simple action, such as moving the a-side bishop one square toward the h-file, might be agreeable, since there is no question of preserving randomness. Once the bishops are on opposite colored squares, if the king is not between the rooks, it should trade places with the nearest rook.
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John Kipling Lewis's "Castling in Chess960: An appeal for simplicity"[10] proposes the same rules for the initial position as Chess960, but proposes an alternative set of castling rules which Lewis has named "Orthodoxed Castling". The preconditions for castling are the same as in Chess960, but when castling,
... the king is transferred from its original square two squares towards (or over) the rook, then that rook is transferred to the square the king has just crossed (if it is not already there). If the king and rook are adjacent in a corner and the king cannot move two spaces over the rook, then the king and rook exchange squares.
Unlike Chess960, the final position after castling in Chess480 will usually not be the same as the final position of a castling move in traditional chess. Lewis argues that this alternative better conforms to how the castling move was historically developed.
Lewis has named this chess variation "Chess480"; it follows the rules of Chess960 with the exception of the castling rules. There are other claims to the nomenclature 'Chess480'; Reinhard Scharnagl defines it as the white queen is always to the left of the white king.
Although a Chess480 game can start with any of 960 starting positions, half of these are actually mirror positions that theoretically don't change the games' tactics. Another way of defining Chess480 is that the white king must always be located on a dark square. Another satisfactory definition is that the white king must always be on a light square. The point is that half the positions are mirror image reversals of the other half. It is really up to the individual to decide how to filter the 480 positions.
David O'Shaughnessy argues in "Castling in Chess480: An appeal for sanity"[11] that the Chess480 rules are often not useful from a gameplay perspective. In about 66% of starting positions, players have the options of castling deeper into the wing the king started on, or castling into the center of the board (when the king starts on the b-, c-, f-, or g-files). To quote from the wiki Chess page "Castling is an important goal in the early part of a game, because it serves two valuable purposes: it moves the king into a safer position away from the center of the board, and it moves the rook to a more active position in the center of the board". An example of poor castling options is a position where the kings start on g1 and g8 respectively. There will be no possibility of "opposite-side castling" where each player's pawns are free to be used as attacking weapons (as in many Sicilian variations), as the kings scope for movement is very restricted (it can only move to the h- or e-file). These "problem positions" play well with Chess960 castling rules.
There are other chess variants with rules similar to Chess960. These include: