Capablanca random chess
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Capablanca random chess (CRC) is a chess variant invented by Reinhard Scharnagl in 2004. It combines the piece set and 10×8 board from Capablanca chess with the permutation idea of Fischer random chess (FRC or Chess960). This game won a contest in 2005 held at The Chess Variant Pages to design a variant based upon the theme of the number 10.
The rules are the same as in Capablanca chess except the initial setup is randomized. White and black pieces are set up in symmetrical position. The pieces on the first rank are placed randomly with the following restrictions:
- Bishops must be on opposite-colored squares.
- The queen and the archbishop (which are composite pieces possessing, in part, the movement of bishops) must also start on opposite-colored squares.
- The king must be between the rooks.
- All pawns must be protected in the initial setup.
- The starting position must be different from that of Gothic chess (i.e. RNBQCKABNR).
- Starting positions with neighbouring bishops must be avoided.
The first restriction is taken from FRC for the purpose of balancing the power of colorbound bishops. The second restriction is based upon the first restriction but extrapolated to the piece set used by CRC. The third restriction is taken from FRC to preserve castling ability. The fourth restriction helps to minimize the advantage held by White in having the first move. The fifth restriction is to avoid possible legal issues in America with Gothic chess, which was formerly protected by a US patent. The sixth restriction was introduced later upon discovery by Scharnagl that such positions might increase the advantage of first move for White.
Together, these six rules restrict the opening setup to 12,118 starting positions.
Extended FEN encoding
Within Capablanca random chess, X-FEN is used (to represent positions).