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This page is written by the game's inventor, Mark Hedden.

Mercurial Chess

By Mark Hedden


This variant is named after Mercury, innermost planet of the solar system. It is a small world, as is this variant. It also moves through Earth's skies quickly. Because of this, it has long been associated by alchemists and astrologers with passion, almost as much as Mars. So, because of this variant's small size and rapid changes in positions, I felt that Mercury provides a good analogy for it.

Opening Position

   7        K
   6  D N R S N D
   5  P P P P P P
   4  . . . . . .    . .
   3  . . . . . .    . .
   2  p p p p p p
   1  d n s r n d
   0      k

      a b c d e f    * @

White: Pawns: a2, b2, c2, d2, e2, f2; Dragon: a1, f1; Knights: b1, e1; 
King: c0; Rook: d1; Rocket: c1;

Black: Pawns: a5, b5, c5, d5, e5, f5; Dragon: a6, f6; Knights: b6, e6; 
King: d7; Rook: c6; Rocket: d6;



Mercurial chess is played in all ways exactly as F.I.D.E. Chess, except where specified otherwise.

The Pieces

Pawns: Pawns move one square diagonally forward. When capturing, they jump over an any piece diagonally in front of them to the square beyond it, capturing it. When a pawn reach either the 6th or 7th row for white or the 1st or 0th row for black, it promotes to any piece except for a king.

For example, in the following position, the white pawn on c1 could jump over the black king on b2, capturing it and landing on a3.

   3 . . .
   2 . K .
   1 . . p
     a b c


Knight: The Knight moves and captures as does its FIDE equivalent.

Rook: The Rook moves and captures as does its FIDE equivalent.

King: The King also moves and captures as its FIDE equivalent.

Dragon: The Dragon either jumps 2 squares diagonally or moves one square orthogonally. It captures in the same manner.

(Or in other words, it moves like a combined Alfil and Wazir.)

Rocket: The rocket moves one square orthogonally forward or one square diagonally forward. It captures in the same manner.

The rocket can also move itself and one other piece to the Satellite board, where they can drop back onto the main board (see below).


When one piece captures another piece, that piece is not taken off of the board. Instead, it is placed underneath the capturing piece (so checkers pieces are recommended for the game). As other pieces are captured, they too are stacked beneath the piece. If that piece is in turn captured, all of the pieces it has taken are 'liberated'. The player to whom they originally belonged to gets to keep them in hand, and may later drop them to any unoccupied square on the main board. Dropping constitues a full move. Pawns may not be dropped on a square where they would promote (the 6th or 7th rank for white, the 0th or 1st rank for black).

The Satellite Board

The squares *3, *4 and @3, @4 are a second board, seperate from the main one. It is called the Satellite board. A rocket may on any given turn 'blast off' to any unoccupied square on the satellite. Once on the Satellite, the rocket may use a turn to drop down to any unoccupied square on the board. This increases the rocket's power considerably.

Also, the rocket may help another piece get onto the Satellite board. A rocket may take any adjacent, friendly piece (aside from Kings and pawns) up with it to any other non-occupied square on the satellite. That piece may later drop down by itself, in precisely the same manner as the rocket does.

The Satellite board is a normal board, and pieces on it may move and capture normally. So a white Rook on @4 could capture a black Rocket on @3.

Winning the Game

The first player who captures his opponent's King wins the game. There is no check, although you can call it if you want to. Draws occur either by agreement or when 30 moves have been made without a pawn move or a capture.


As there is a very small area of board not initially occupied, the board will quickly close up. The Rocket's power to drop down, and to help others drop down, should tend to loosen things up a bit. The ability to rescue captured pieces should do the same, and also increase the length of the game.

It's interesting to note that the rook is, in fact, the most powerful piece on the board. Dragons and Knights work rather nicely on this size board, and are about equal in strength. Many small variants use Queens and such on this size of a board, but I've always thought that they're way too powerful to be used in such a small area.

Zillions of Games

There is an implementation of Mercurial Chess for Zillions of games. You can download it here:

Written by Mark Hedden. HTML Conversion by Peter Aronson.
WWW page created: August 4th, 2001.