Brusky's Variant

Origin

Invented by Yakov Brusky in 1966 and preserved in D. B. Pritchard's Encyclopedia of Chess Variants, Brusky's hexagonal chess adapts orthodox chess to a hexagon by turning the board 30° — ranks run horizontally, and files slant up the board. Piece movement is otherwise identical to Glinski's; pawns and castling are where things get interesting.

Board

A horizontally-symmetric elongated hexagon of 84 cells in three colours, thirteen files wide (a through m) and eight ranks tall. Ranks widen from 9 cells at the top and bottom to 12 cells across the middle two ranks (9 · 10 · 11 · 12 · 12 · 11 · 10 · 9).

Starting Position

Each side has 19 pieces:

• 1 King · 1 Queen
• 2 Rooks · 3 Bishops · 2 Knights
• 10 Pawns (the second rank has ten squares)

White's back rank, from left to right:

Rook — Knight — Bishop — Queen — Bishop — King — Bishop — Knight — Rook

White's back rank sits on files e1–m1with the king on j1 and the queen on h1. Black is the 180° rotation: back rank on a8–i8, king on d8, queen on f8.

How Pieces Move

Rook, Bishop, Queen, Knight, King

Identical to Glinski's. Rooks slide the six orthogonal hex directions; bishops slide the six hex diagonals; the queen combines both; kings step one hex in any of twelve directions; knights leap the standard hex knight shape (twelve destinations).

Pawn

A pawn has two forward-orthogonal step directions (left-forward and right-forward). On its first move it may double-step in one of those two directions — both steps must go in the same direction, it cannot bend.

Slanted captures: a pawn captures on the two forward slanted diagonals.

Pawns do not capture straight forward along the vertical diagonal — only the two slanted diagonals above.

Adjacent-enemy cross-block: if an enemy piece sits on one of the pawn's two forward-orthogonal cells, the pawn is blocked in the OTHER forward direction as well. Friendly pieces do not cross-block.

En passant: as in classical chess — after an enemy pawn double-steps, an adjacent pawn may capture it on the next move by moving to the square it passed over.

Promotion: a pawn reaching the enemy's back rank (rank 8 for White, rank 1 for Black) promotes to Queen, Rook, Bishop, or Knight.

Castling

Brusky's keeps castling. Two flavours, matching classical chess terminology:

• Kingside: the king moves two squares toward the nearer rook; the rook jumps to the square adjacent to the king on the king's other side.
• Queenside: the king moves three squares toward the far rook; the rook jumps to the square adjacent to the king on the king's other side.

As in classical chess, castling requires that the king and the involved rook have not previously moved, that all squares between them are empty, and that the king is not in check, does not pass through an attacked square, and does not land on an attacked square.

Notation: O-O · kingside · O-O-O · queenside.

Winning, Drawing, and Check

Checkmate wins. Stalemate is a draw. Threefold repetition draws automatically. Both players may agree to a draw at any time.

Differences from Glinski's, McCooey's, and Shafran's

• Board orientation: pointy-top hexes with horizontal ranks and slanting files (the other three variants use flat-top hexes with vertical files).
• Board size: irregular 84-cell hexagon — larger than Shafran's 70, smaller than Glinski/McCooey's 91.
• Back rank order: R N B Q B K B N R — three bishops with the king and queen split across the middle bishop.
• Ten pawns: the pawn rank is longer than the back rank, so each side starts with 10 pawns.
• No forward-diagonal capture: unlike the other three variants, Brusky's pawns cannot capture straight forward along the vertical diagonal.
• Adjacent-enemy cross-block: a pawn with an enemy on one forward-orthogonal cell is blocked in both forward directions.
• Castling: two flavours (kingside/queenside), not four; queenside travels one square further than kingside.