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This page is written by the game's inventor, Peter Aronson.

Potential/Demotion Chess

By Peter Aronson


          Potential/Demotion Chess is like standard FIDE Chess, except that pieces are allowed make the moves of lower-ranked pieces in addition to their normal moves, but if they make any move that a lower-ranked piece could make, they become that lower-ranked piece. The game is a sort of odd cousin of Fergus Duniho's Metamorph Chess.

General Rules

          The rules of Potential/Demotion Chess are identical to those of orthodox chess, except when noted otherwise.

Pieces are ranked, highest to lowest: Queen->Rook->Bishop->Knight->Pawn (Kings are outside the ranking system).

Demotion and Potential works as follows:

          The board and setup are as usual, and so are not shown here. However, if you wished to better represent the pieces actual movement potential visually, and you had the right sorts of pieces, you could replace the Queens and Rooks with Amazons, the Bishops with Cardinals, and the Knights with Dragons, and still play the game the same way.

The Movement of Pieces

          The King and the Pawns both move as they do in orthodox chess, including castling, double-move, en-passant and promotion.

          Any piece, when moving as a Pawn, may make a double move forward from the second rank any time it finds itself on that rank. Also, any piece, moving as a Pawn may make a Pawn's en-passant capture of a Pawn that has just double-moved to its immediate left or right. Either of these moves causes the piece making the move or capture to become a Pawn itself. Finally, any piece other than the King on the 7th rank may make a Pawn's move (either capturing or non-capturing) to the 8th rank, and promote to a Queen, Rook, Bishop or Knight.

          Queens are unstable -- they always change into something else when they move, since they have no unique moves not also used by a lower-ranked piece. Otherwise, Queens move like Rooks, which are discussed in more detail below.

          Rooks are very powerful, since they can move like a Rook, like a Bishop, like a Knight or like a Pawn, as long as they don't mind possibly turning into something else. The following diagram indicates which moves turn a Rook into what other pieces:


The Rook is represented by the red circle. The white pawns show where the Rook, if it makes a noncapturing move, will turn into a Pawn (capturing moves to those squares leave it a Rook). The black Pawns show where the Rook, if it makes a capturing move will also turn into a Pawn (a non-capturing move to those squares will turn it into a Bishop). The green Knights show where the Rook can move and turn into a Knight, the yellow Bishops show where the Rook can move and turn into a Bishop, and the red Rooks show where the Rook can move and remain a Rook. The Queen moves essentially the same, but does not get to remain a Queen.

          Bishops move much like Rooks, but without the Rook components; that is, anywhere on the above diagram represented by a Pawn, a Knight or a Bishop (but the white Pawn moves must be non-capturing), with the same conversion rules.

          Knights may make usual Knight moves, or make Pawn moves and become a Pawn.


          There is a great deal of power on the board at first, since each side starts with effectively three Amazons, and two Cardinals and two Dragons, but pieces weaken if actually used. But there still may be too much power on the board for good play.

          Potential/Demotion Chess was inspired by David Howe's Potential Chess, Tony Quintanilla's Chameleon, Sergey Sirokin's Chameleon Chess, and Fergus Duniho's many mutating piece Chess variants, from Sentai Chess through Fusion Diamond 41.

          Potential/Demotion Chess is the sort of set of rules changes to orthodox chess that João Pedro Neto describes as a Mutator, and could as easily be applied to another form of Chess such as Xiangqi or Makruk, or combined with other mutators such as progressive play.

Zillions of Games

          I have written an implementation of Potential/Demotion for Zillions of games. You can download it here:

Written by Peter Aronson.
WWW page created: April 8th, 2001.