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This page is written by the game's inventor, LUCIANO IMOTO.


LOCKING CHESS reinvented chess with the option of moving pieces on top of each other and moving them over each other afterwards, and winning with new types of checkmates. This piece climbing allows for new opening moves, and for the first time, a King can also check and win with Royal Lockmate or Royal Mate!

In LOCKING CHESS, chess players compete in two territories, one at the level of the chessboard and the other above it, moving their pieces over each other as if they were squares to climb on. Controlling this “airspace” will be vital to create traps, avoid blunders and unexpected captures.

LOCKING CHESS consolidated a third dimension of the chessboard, inaugurating an arsenal of strategic plans and even more complex and challenging tactical themes!


The same pieces, board and setup as Chess.


You can play with cubic chess pieces, similar to the Bauhaus model, to make it easier to move and quickly balance them on top of each other. Staunton and classic model pieces can be adapted to allow for a dynamic stacking between pieces.


BEFORE YOU BEGIN: If you've never played chess, first learn its basic rules. Once you know the basics, you're ready to play LOCKING CHESS!


White always starts the game.


GOAL: Checkmate or Lockmate the opposing King.



1. In LOCKING CHESS, pieces on the board level can rise and settle on their own pieces according to their capturing move. A piece on the board level, in all phases of the game, can only climb atop pieces of its color. Once over another piece, the pieces can move normally over the others that are on the board level, whether of their color or the opponent's.

2. The Pawn Overlaying: The pawn is the only piece whose diagonal capture move is different from its advance move. Thus, the white pawn on its initial square a2, for example, can climb any piece of its color that is on squares a3, a4 or b3 in its first move. A white pawn over a piece on d4, for example, can advance and go down to the empty c5, d5 or e5 square, or advance over any piece, whether of its color or the opponent's, that is on the board level in one of those same squares. This white pawn over another piece of its color on d4, as an example, can capture the opponent's piece that is also overlaided on c5 or e5 (see CAPTURE RULES).

3. A piece on top of another piece is an Overlaided piece. A piece overlaiding another piece of its color is considered an Equal overlay. If overlaided on an opposing piece, it is an Opposite overlay. A piece underneath another piece is a Locked piece.

4. Maximum of one overlaiding per piece on chessboard level.

5. An overlaided piece, according to its movement, can move one or more squares over its own pieces and those of the opponent that are on the level of the board. And you can go down from them at any time to get back to the board level. When you land on a piece of yours or an opponent's piece on the board level, it will “lock” it there, thus preventing its movement, but not its capture (see CAPTURE RULES).

6. Overlaided pieces cannot jump over (with the exception of Knights) nor land on another already overlaided piece (see Rule 4).

7. When an overlaided piece moves, either down and back to the board level or atop another piece, the piece that was underneath it will become “free”. And the pieces on the board level that become “free” can move, capture or climb on, and be captured or overlaided/locked again.

8. Any overlaided piece, including the King, can land on and “lock” the opposing King if it is on board level. Pieces at board level and overlaided can also lock their own King that is at board level by climbing or landing on it, thus leaving it equally vulnerable to check.

9. The King at the board level cannot move up and overlay a friendly piece on the square next to the opposing King's overlaided, but it can move to the square next to the opponent's overlaided King and give it check if the piece under the opponent's King is of Equal overlay. And an overlaided King also cannot move upon a piece next to the opposing overlaided King, nor move down to a square next to the other King on the board level (see CHECKMATES RULES).

10. Promotion: when a pawn reaches its opponent's first rank, even if it overlays one of its own or the opponent's pieces on that square, it is immediately promoted to Queen, or Rook, or Knight, or Bishop, according to the chess player's decision. If you choose to promote the overlaiding pawn to Queen or underpromote it to Rook, Knight or Bishop, and there is a friendly or opposing piece below it on its rank and promotion square, including one of the Kings, this piece will be “locked”. And if a pawn at the board level captures an opposing piece “locked” in an Opposite overlay on its promotion rank, it will be immediately promoted and that newly promoted piece will be locked in place of the piece it captured.



1. Pieces on the board level can capture both the opponent's pieces that are on that level and the opponent's two pieces in Equal overlay!

2. Only a free pawn on the board level (that is, with no piece overlaying it) can capture en passant.

3. A piece on the board level is allowed to capture the opponent's pieces that are locked under a piece in Opposite overlay. Consequently, that capturing piece will take the place of the captured piece and will be “locked” under its own piece in an Equal overlay.

4. The Knight is the only piece that, being at the level of the board, can capture the piece in Opposite overlay of the opponent that is on top. And if they are pieces on an Equal overlay, then both will be captured by the Knight.

5. The Knight is also the only piece that, being overlaided on a piece of its color, can capture the opponent's piece that is free on the board level.

6. An Opposite overlaided piece on top can only be captured by other overlaided pieces or by a Knight on the board level. By capturing the piece on top and taking its place, the piece below will remain “locked”.

7. When a overlaided piece captures the opponent's two pieces in Equal overlay, it will occupy its square, thus returning to the level of the board. A piece on the board level can also simultaneously capture both opponent's pieces in Equal overlay.

8. A piece, whether at board level or atop another piece, cannot overlay its King if there is an overlaiding piece of the opponent capable of capturing them in that Equal overlay.



En Passant Overlay (epo): this LOCKING CHESS law allows a pawn overlaying exception. In the pawn's initial two-square advance, if there is an opponent's pawn overlaided on the adjacent file and on the same rank, it can overlay the moved pawn and “lock” it back in the square it jumped. This extra special rule in LOCKING CHESS prevents a pawn from using the initial two-square advance to pass alongside an opponent's overlaided pawn without being locked.

As with the en passant capture, the En Passant Overlay must be done immediately after the pawn has advanced two squares. If the player decides not to do it, he will lose the right to do so later. Like any other move, if the En Passant Overlay is the only valid move remaining, it must be made. 

Castlock: in addition to traditional castling, in LOCKING CHESS there is the alternative of Castlock, a new special double move with the King and one of the Rooks. The move consists of moving the King on the first rank sideways by two squares towards the Rook with which you want to castle, and the chosen Rook overlays the King after the “jump”. The objectives are to protect the King, taking it off center, improve position and/or check if the opposing King is in an Equal overlay on the same Rook file.

As in traditional castling, there are two types of Castlock: Long Castlock (when performed with the furthest Rook from the Queenside) and Short Castlock (when performed with the closest Rook from the Kingside). The other conditions to allow Castlock are the same as for traditional castling, with the addition that the Rook, when overlaying the King (Equal overlay), does not remain in the crosshairs of the attack of an overlaided opposing piece (see CAPTURE RULES).



1. When a “free” King — that is, at the level of the board and without any piece overlaiding it — is in check and there is no way for it to escape to another square, capture, lock or block the attacking piece, will be normal checkmate.

2. A King “locked” at the board level, under a piece of its color (Equal overlay), is subject to check. And if it is attacked and there is no way to lock, capture or block the check, it will be Lockmate, that is, a checkmate with the King immobilized!

3. A King “locked” at the board level, with any enemy piece (including the opponent's King) overlaided on it, will also be vulnerable to Lockmate!

4. If a “refugee” King on top of a piece of its own color (Equal overlay) is in check by an opponent's piece at the level of the board, and there is no way to go down, escape, capture, block or lock the attack, it will be a Refugee Mate.

5. If a “refugee” King in an Opposed overlay is in check by an overlaided opponent’s piece or an opponent’s Knight at the level of the board, and there is no way to get down, escape, capture, block or lock the next attack, it will also be a Refugee Mate.

6. A “free” King at board level can move into the square next to an overlaided opponent's King in Equal overlay and give it a point-blank check directly! And if there is no way for this “refugee” King to come down, escape or lock this check, it will be the Royal Mate!

7. A “free” King at the level of the board or overlaiding another piece can move or go down to the square next to the opponent’s locked King and give check to it only if the opponent’s piece that is eventually locking its own King is not able to lock it by overlaiding it. If there is no way to save the “locked” King from this point-blank check applied by a King at the board level, then it will be the Royal Lockmate!



1. A “locked” King with any other opponent's piece overlaided on it, without being in check and without other valid moves, will be paralyzed and therefore drowned. This situation is called “Lockout” and will be a draw.

2. If the only move of a “refugee” King that is not in check leaves it vulnerable to checkmate, it will be in “Deadlock”, that is, drowned, and it will also be a draw.

The other stalemate and draw rules are the traditional ones.


I created LOCKING CHESS in 2022, inaugurating the New Era of Caissa, a movement to renew Chess. LOCKING CHESS is my humble contribution to help complete the traditional chess.

This game notation below is a sample of LOCKING CHESS with a Lockmate in 32 moves and easy to understand. On the official LOCKINGCHESS.COM website there are other Demo Games for readers to appreciate the subtleties of the LOCKING CHESS.

1.e4           e5

2.Nf3         Qe8*

3.Bg2*      Bg7*

4.O-O* (Short Castlock)  Nf6

5.Re1         Be5*

6.Ra2*      d5

7.d3           Nc6

8.Be3         d4

9.Bxd4       Nxd4

10.Nxd4    Bd4*

11.Rd1*    Ba7*

12.Nb5      Qb5*

13.Rb1*    Bg5

14.f3          Bxf3

15.Bf3*     Qxb1*

16.Qxb1    Bg1*

17.Nxc7+ Ke7

18.Nxa8    Rxa8

19.Ra8*    Nh5

20.gxBf3* Nf4 (threating Lockmate with 21. ...  Nh3#)

21.Qf1       Kf6

22.Bd5      Kg5

23.Bxb7     Kh4

24.Qf2+    Bf2*

25.BxRa8*  Kh3

26.Ra2*      h5

27.RxBf2*  h4

28.Rf4*       f6?


30.Rh4*      Ng6

31.Kh2*      NxRh4*

32.Kg3#      1 - 0

* In LOCKING CHESS algebraic notation, the move in which one of the pieces overlays the other is underlined or annotated with an asterisk symbol.


P.S.: The variants that come closest to LOCKING CHESS piece stacking concept are “Crescendo Chess” (1973) and “Troja” (1996).

This 'user submitted' page is a collaboration between the posting user and the Chess Variant Pages. Registered contributors to the Chess Variant Pages have the ability to post their own works, subject to review and editing by the Chess Variant Pages Editorial Staff.


Last revised by LUCIANO IMOTO.

Web page created: 2023-06-27. Web page last updated: 2023-10-22