Portal Chess

Portal Chess is a variant, invented by David Howe in 1997.

Description

Portal Chess is a chess variant that addresses the problem of one player or the other getting to make the first move. This is solved by splitting the board up into two boards and letting each player go first on their board. Players may move pieces from one board to the other only under very limited conditions.

Note that this variant is a general modifier and may be applied to many other chess variants in addition to usual or normal chess. Below I describe its application to normal chess.

Game setup and equipment

1 or 2 orthodox chess sets

Initial setup for two chess sets:

                 Board A                             Board B
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    | r | n | b | q |   | b | n | r |   | r | n | b | q | k | b | n | r |
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    | p | p | p | p | p | p | p | p |   | p | p | p | p | p | p | p | p |
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    |*A2|   |   |   |   |   |   |*A4|   |*B2|   |   |   |   |   |   |*B4|
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    |*A1|   |   |   |   |   |   |*A3|   |*B1|   |   |   |   |   |   |*B3|
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    | P | P | P | P | P | P | P | P |   | P | P | P | P | P | P | P | P |
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+
    | R | N | B | Q | K | B | N | R |   | R | N | B | Q |   | B | N | R |
    +---+---+---+---+---+---+---+---+   +---+---+---+---+---+---+---+---+

Initial setup for one chess set:
(The line down the middle cannot be crossed. Treat the two sides as two different boards.)

         Side A           Side B
    +---+---+---+---++---+---+---+---+
    | r | n | b | q || k | b | n | r |
    +---+---+---+---++---+---+---+---+
    | p | p | p | p || p | p | p | p |
    +---+---+---+---++---+---+---+---+
    |   |   |   |   ||   |   |   |   |
    +---+---+---+---++---+---+---+---+
    |*A2|   |   |   ||   |   |   |*B2|
    +---+---+---+---++---+---+---+---+
    |*A1|   |   |   ||   |   |   |*B1|
    +---+---+---+---++---+---+---+---+
    |   |   |   |   ||   |   |   |   |
    +---+---+---+---++---+---+---+---+
    | P | P | P | P || P | P | P | P |
    +---+---+---+---++---+---+---+---+
    | R | N | B | K || Q | B | N | R |
    +---+---+---+---++---+---+---+---+

Rules

A single turn consists of the White player moving a piece on one board and the Black player moving a piece on the other board.
On turn 1, White moves on board A, Black on board B. Each turn, the players switch boards.
Movement rules are as in orthodox chess. Once a piece is touched, it must be moved. Once you let go of a piece after it has been moved, that move may not be taken back.
Moving pieces between boards (teleporting). To move a piece from one board to the other, the piece must be on one of the portal squares (a square marked with an asterisk (*)). When it is the player's move on the board where the piece is to be transferred from...
1. The player waits for the opponent to make their move, then states their intention to teleport, but moves no pieces.
2. On the next turn, the player waits for their opponent to move.
3. The player then takes the piece from its current board and places it on the corresponding square on the other board (eg. from *A1 to *B1). This counts as the player's move (ie. the player may not also make a normal move, nor may they declare intent to teleport).
If an opposing piece occupies the square being teleported to, it is captured.
If a friendly piece occupies the square being teleported to, the teleport is not allowed. If the player cannot teleport after declaring intent to teleport, their turn is simply lost.
The teleporting player may cause their King to be exposed by teleporting a piece that is blocking check. This is allowed because it will be their turn on that board next. The player has simply caused themselves to be put in check.
A declaration to teleport does not specify a particular piece, only the intent to teleport. The piece to be moved is decided when the player is actually about to move a piece to the other board.
Both players may declare intent to teleport on the same turn. In this case, the moving of the pieces between boards is considered to be simultaneous. If both players have a choice of which piece to teleport, then they should each write down the piece they intend to move. After both players have written their move, they show each other and the moves are made.
Moving a King into check. Here are some instances where a King is being moved into check (or is already in check). These are considered to be illegal moves:
- At the beginning of a turn, player 1 moves their King onto a portal square and player 2 has a piece on the corresponding portal square on the other board.
- At the beginning of a turn, player 1 has their King on a portal square and player 2 has a pece on the corresponding portal square on the other board. Player 1 moves a piece other than their King.
It is possible that both players may checkmate each other simultaneously. In this case the game is considered a draw.

Written by David Howe. (The first line was written by Hans Bodlaender.)

WWW page created: May 6, 1997.