Fischer Random Chess was invented by former World Chess champion Bobby Fischer. He announced the rules in June 1996 in Argentina. The original Zillions version was implemented by Pierre Tourigny in Sept. 1999. This larger (10x10) board variant was developed directly upon that version.

The top two listed variants from Franklin Grand Chess makes use of the Fischer Random Chess rules.

The Brawns were added to maintain a stronger level of conflict upon the larger than traditional board size. Released during www.ChessVariants.org's 10th year anniversary contest.

Fischer Random rules (modified for use with FGC)
Two combination pieces, a Chancellor and an Archbishop have been added to the 10-column setup. The Chancellor can also be used for Castling with the King where permitted (same as a Rook). All Pawn pieces can promote to these two pieces as well as any other usual pieces.

The opening setup for Pawns includes the addition of four Doubled Pawns (Brawns) which can slide forward 1 or 2 and captures 2 steps away. Their opening move permits an extra step; same as with regular Pawns. Otherwise their behaviour is the same.

The opening setup for the officers on the First and Last Rows is chosen randomly while satisfying the following conditions:

• The King must be placed somewhere between the Rooks.
• The two Bishops must start on squares of different colours.
• The Black setup mirrors the White setup, i.e. pieces on the same file are of the same type. For example, if there is a White Queen on a1, there is a Black Queen on a10.

CASTLING [10x10 setup] is done in the following way:
When castling left, the King moves to Column C and the Column A-or-B Rook (or Chancellor) moves to D. When castling right the King moves to Column I and the Rook /Chancellor moves to H. Another way of remembering this is that columns C & I are each 3 spaces from the standard opening position of the King (column F, here). The following conditions must be true: the King must not move to, from or over an attacked square; the King and Rook /Chancellor have never moved; there is no other piece on any square over which the King and Rook (or Chancellor) move.

Note that if the King starts the game on a castling destination square (c or i), castling on that side is done by moving the Rook /Chancellor instead of the King.