Rules of QuadLevel 3D Chess

Set Up

QuadLevel uses four half‑boards stacked vertically (4×8×4). Two complete sets of chessmen are required – including two Kings and two Queens. On the top level the white Knight begins on a white square, followed by the sequence Rook, Knight, Bishop, Rook. Queens begin on their own color as in classical chess. The ideal view is from the long side with your pieces on the left, playing left to right.

The Three‑Dimensional Concept

Traditional chess uses X and Y movement. QuadLevel adds the Z dimension. Pieces move normally on each flat board (X–Y plane) and may also move in the rotated Y–Z plane. This preserves the spirit of chess while opening a vertical battlefield. See the Youtube video

Change In Distance Rule (CID)

Diagonal movement must change the distance between players. A piece starting on flank A must remain on flank A when changing boards. Pawn, Knight, and Bishop moves must advance or retreat toward the opponent. This keeps Bishops and Knights from roaming the back ranks and preserves game balance. Watch the In defense of the CID Video

Piece Movement

Pawn

Advances one square (two on first move). Captures diagonally ahead on the same board, up one board, or down one board. En‑passant and promotion operate as in classical chess.

Bishop

Moves diagonally on its color in eight directions across levels.

Rook

Moves in straight lines across rows, columns, and vertically between boards with unlimited range.

Knight

L‑shaped jump: two squares/boards in one direction and one in another. Knights jump over pieces and retain much of their classical strength.

Queen

Combines powers of Bishop and Rook across all levels.

King

Kings move one square in any direction.

Castling

Four castling options exist for each King – toward edges or between levels – provided no squares are attacked and the pieces involved have not moved. In each case a Bishop and a Knight must be out of the way, as you must imagine the pieces slide like the arrows.

Estimated Power Values

Pawn 1 • Knight 2.85 • Bishop 2.85 • Rook 4 • Queen 8

In the beginning my father insisted that the power was the same as regular chess. Later I thought as others that first initially studied the game, that the Bishop was under powered, Later I came to realize in practice, that the Bishop is not. Trading Bishops for Knights is not a power move.

Check, Mate, and Draw

A King in check must be defended immediately. Checkmate occurs when no legal defense exists. Standard draws include repetition, 50‑move rule, and stalemate. Watch the Two Kings YouTube

Standard Version

The game ends, when either King is Checkmated or a Double-Check King fork cannot be nullified.

Original Variant – “Destroy Both Kings”

When a King is checkmated, it is removed from the board and the remaining King becomes locked (it may not move).

• A locked King may still be captured, even by a simple check.
• If both Kings are in check simultaneously, the player chooses which King is removed (a rare “Sophie’s choice”); the other retreats to safety and becomes locked.

Exceptions:

• A stalemate unlocks the King.
• An opposing King may not capture by moving adjacent to the locked King.

Other Variants

There have been players that are fundamentally opposed to playing QuadLevel with the CID enforced, and have tried to play other variants on this setup. Sometimes they have decided to give certain pieces different kinds of 3D powers but not all of them. Such as giving the Queen and Bishop side-stepping powers, but not the Knight and King. This comes from the belief that the Bishop is cramped. It only feels that way. (Try some Standard games against the strongest engine, Zillions of Games, it can beat me often, trade Bishops for Knights at your whimsy, doesn't mean you will win...) If you gave the power to the King, the King(s) will have more running room.

Minimum Mating Material

Knight & Bishop, Two Knights, Two Bishops (on opposite colors), Lone Rook.
These are listed in order of how difficult it is to force mate. If you played without the CID, likely the minimums would be larger.

Notation

Format: {Piece}{Level}{Column}{Rank}. Example: 1) 2c4 2c5. Castling example: 2O‑O1.