Fischer Random Chess
Recognized Variant of the Month for April 2002. Twelve times per year we will select a Recognized Variant for special consideration. Its web page will be reworked and improved and a connecting link displayed on all of our CV Pages. We hope to encourage CVPhiles to read about, play and explore this featured variant.
IntroductionBobby Fischer, a former world chess champion, proposed a variant of Orthodox Chess wherein the initial setup of pieces is chosen randomly. Fischer thereby joined the ranks of other former world champions, such as Capablanca, who proposed changes to the rules of chess -- none of which were ever implemented. Fischer Random Chess is somewhat similar to the older Shuffle Chess, or Prechess (or other related variants), yet has a unique style of its own. An extensive introduction and history of the game was written by Eric van Reem.
SetupFischer Random Chess is played with an Orthodox Chess set but employs a randomly generated array. Each new setup is determined by a computer program (or manual procedure) which assigns starting squares according to the following guidelines:
- 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.
PiecesOrthodox Chess pieces are used exclusively.
RulesOrthodox Chess rules apply when applicable.
Castling may be performed under the following conditions:
- Neither King nor Rook has moved.
- The King is not in check before or after castling.
- No square through which the King must move is under attack.
- All squares between King and Rook are vacant.
- No other pieces occupy any of the squares passed over by the King or Rook.
- The castling move does not result in a capture.
A King may castle with its a-side Rook or its h-side Rook. When castling a-side, the King and Rook go to the same spaces they would go when Queen-side castling in Chess. When castling h-side, the King and Rook go to the same spaces they would go when King-side castling in Chess. This table shows where the King and Rook end up for each type of castling.
|White castles a-side||Kc1, Rd1|
|White castles h-side||Kg1, Rf1|
|Black castles a-side||Kc8, Rd8|
|Black castles h-side||Kg8, Rf8|
More detailed rules may read at Bobby Fischer's website:
Computer PlayIf you have [an error occurred while processing this directive] Zillions of Games installed on your computer, you can play this game. Download file: fischer.zip.
Number of Possible Arrays
Terumi Kaneyasu (Sam Sloan?) writes:
Fischer Random Chess has 960 legal arrays. This number is determined as follows:
First, place the two Bishops. There are 16 different ways for one bishop to be on a white square and the other Bishop to be on a black square.
That leaves six empty squares. Now, place the King somewhere between the two Rooks. There are 20 different ways for a King and two Rooks to occupy six squares with the King in between.
That leaves three squares for the two Knights and the Queen. There are three possible ways to place these pieces.
Thus, there are 16 x 20 x 3 (960) legal arrays in Fischer Random Chess.
Written by various authors. Information based on news postings by Terumi Kaneyasu; send to me by Terumi Kaneyasu and Dennis Breuker. Modest Solans noticed an error in an earlier version. The picture of Fischer is from Palle Mathiasen's World Chess Champions site. Edited by John William Brown for the occasion of this variant being selected Recognized Variant of the Month for April 2002. Rules corrected by Fergus Duniho in May, 2004.
WWW page created: 1995 or 1996.