Standard chess
Movement, capture, check/checkmate, castling, en passant follow normal chess rules; promotion lets you choose Queen, Rook, Bishop or Knight.
TWO-LAYER CHESS • TUNNEL RULES
Think beyond the next move.
Think through the board.
A two-layer chess variant with Surface and Underground boards, bidirectional tunneling, same-square ambushes, and unlimited cross-layer knight jumps.
2 LAYERS
Two tactical layers
Every piece starts on Surface and may exist on either Surface or Underground within the same 8×8 coordinates.
Bidirectional tunneling
Tunneling down and back up are both legal; a piece may capture an enemy on the matching square of the other layer.
Limited tunneling
Each side always has at least one free tunnel; the maximum tracks surviving pawns across both boards, with no normal tunneling on consecutive turns.
Knight breaks depth
Knights move or capture in an L across layers without limit and without consuming normal tunnel quota.
Free response
Escaping check by tunneling gives the opponent one tunnel response on the next turn without consuming free quota.