The Chess Variant Pages

This page is written by the game's inventor, Jose Carrillo.

International Fischer Random Chess


International Fischer Random Chess (IFRC) is a variant inspired by International Contemporary Random Chess (ICRC) and Fischer Random Chess (Chess960), played on a Polish or International Draughts (Checkers) 10x10 board:

IFRC applies Chess960 random rules and direct symmetry to a ICRC layout (which was itself inspired by English Random Chess and Contemporary Random Chess)

International Contemporary Random Chess (left diagram, with reverse symmetry) and English Random Chess (right diagram, without any symmetry and an absolutely random setup)


In International Fischer Random Chess the pawns are placed on the players' 3rd rank, with the pieces randomly placed behind the pawns. There are no men on the first and last files or ranks.

All pieces are randomly placed in the players' second rank, à la Fischer, with the restriction that the King must be between the two rooks (to allow FRC castling) and that the Bishops are in opposite color squares.

The opponents’ pieces are placed with direct symmetry (White’s piece at b2 is equivalent to Black’s b9, White’s c2 to Black’s c9, White’s d2 to Black’s d9, White’s e2 to Black’s e9, and so on…)

There are 960 different legal starting positions in International Fischer Random Chess.


Orthodox Chess pieces are exclusively used.


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All rules for Fischer Random Chess (Chess960) apply to IFRC, including FRC castling and en passant. Pawn promotion takes place when pawns reach their 10th rank.


The International Fischer Random Chess castling rules are the same as in the Fischer Random Chess, but ajusted to the International 10x10 board.

In IFRC, depending on the pre-castling position on the castling King and Rook, the castling manoeuvre is performed by one of these four methods:

  • Double-move castling: By on one turn making a move with the king and a move with the rook.
  • Transposition castling: By transposing the position of the king and the rook.
  • King-move-only castling: By making only a move with the king.
  • Rook-move-only castling: By making only a move with the rook.

Castling the King and Rook will be placed as if the player had castled in Orthodox Chess (but relative to the inner 8x8 squares in the 10x10 board).

Thus, after long or d-castling (notated as O-O-O), the King is on the d-square (d2 for White and d9 for Black) and the Rook is on the e-square (e2 for White and e9 for Black). After short or h-castling (notated as O-O), the King is on the h-square (h2 for White and h9 for Black) and the Rook is on the g-square (g2 for White and g9 for Black).

This table shows where the King and Rook end up and the notation for each type of castling.

White castles a-sidec-castlingO-O-OKd2, Re2
White castles j-sideh-castlingO-OKh2, Rg2
Black castles a-sidec-castlingO-O-OKd9, Re9
Black castles j-sideh-castlingO-OKh9, Rg9

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

  • Unmoved: The King and the castling Rook must not have moved before in the game, including a previous castling or a Bishop Adjustment.
  • Un-attacked: All of the squares between the king's initial and final squares (including the initial and final squares) must not be under attack by any opposing piece.
  • Vacant: All 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.
These rules have the following consequences:

  • Castling cannot capture any pieces.
  • The king and castling rook cannot "jump" over any pieces other than each other.
  • A player may castle at most once in a game.
  • If a player moves his king or both of his initial rooks without castling, he may not castle during the rest of the game.
  • In some starting positions, the king or rook (but not both) do not move during castling.
  • In some starting positions, castling can take place as early as the first move.
  • The king may not be in check before or after castling.
  • The king cannot move through check.
  • The king cannot jump over his own rook if and when said rook stands on a “checked” square. This point is best ilustrated by the sample Fischer Random Chess (Chess960) position below where it's illegal for White to g-castle (O-O) with it's e-Rook, as the King would need to jump over an attacked square. Even though the e-square is occupied by a Rook, it is under attack (or 'checked') by Black's Rook on e8.


International Fischer Random Chess (IFRC) was proposed by José Manuel Carrillo-Muñiz, from Puerto Rico in 2008.

Game Courier Preset

International Fischer Random Chess preset

Game Courier Logs

Game Courier Logs for Games of International Fischer Random Chess

To see actual games that have been played on-line, follow the link above.

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By Jose Carrillo.
Web page created: 2008-08-03. Web page last updated: 2008-08-03