Rules & FAQ

Consulchess is played on an enlarged board of 10 files (a-j) instead of the traditional 8 files and 8 ranks (1-8), resulting in 80 squares in total, against the 64 of classical chess. Thus, each side starts with 20 pieces. On the two extra files - flanking the king and the queen - sit two pawns and two Consuls. This means that the king now stands on its own colour.

The two Consuls begin on the d- and g-files, beside the king and queen.

The Consul (C) is the new unique piece at the heart of the variant. It moves like the queen — vertically, horizontally and diagonally — but with a maximum range of three squares.

Within those three squares the Consul may either slide across empty squares or jump over occupied ones. It loses its jumping ability after the first empty square, so a three-square move needs a uniform path: both intermediate squares empty (slide), or both occupied (jump). Mixed paths are illegal.

A Consul may jump over one or two pieces of either colour and capture on the landing square, without capturing the pieces it jumped. A check delivered by a Consul jump is unblockable — the king must move, the Consul must be captured, or the bridge must be broken, for instance by moving one of the pieces involved.

The Consuls worth is roughly comparable to that of a queen. Generally, the consensus is that the consul is stronger in the opening and middlegame as well as in attacking positions due to its larger flexibility, while the queen is stronger in open positions like the endgame due to its long range.

Consulchess replaces (some even say "improves") the classical castling with free castling: on a cleared back rank the king and a rook may swap places in up to 65 different ways (30 toward the kingside, 35 toward the queenside). The full enumeration is below.

Here, the king can move to any non-occupied square towards either side of the board (including the corners) and the rook then can slide to all available squares in the direction of the king’s origin.

Notably, the usual restrictions apply: you may not castle out of check, into check, or through check. Neither piece may have moved before. Finally, the rook may slide only as far as the path is clear, i.e., it cannot jump over enemy or friendly pieces. However, a novelty: a rook may capture an enemy piece on its final square.

En passant works exactly as in classical chess. When a pawn advances two squares and lands next to an enemy pawn, that enemy pawn may capture it as though it had moved only one square — but only on the very next move.

Consulchess 42k is to Consulchess what Chess960 is to classical chess: the back-rank pieces are shuffled into a random starting position. There are exactly 42,000 legal positions — hence “42k”.

The board and the Consul’s moves are unchanged; only the starting position and castling differ. As in Chess960, the bishops start on opposite colours and the king starts between its rooks; Black’s pieces mirror White’s.

Counting the arrangements gives 5 × 5 × 8 × 7 × 6 × 5 × 4 = 168,000, halved twice for the indistinguishable knights and Consuls: 168,000 ÷ 2 ÷ 2 = 42,000.

• Young players in bughouse style (YouTube)↗
• Tibor Nagy vs GM Zoltán Medvegy (YouTube)↗
• Schachfreunde Jülich Chess Club↗
• BSG Jülich chess section↗