The Chess Variant Pages

Check out Symmetric Chess, our featured variant for March, 2024.

This page is written by the game's inventor, Jose Carrillo.

Ajax Bigamous Chess

Ajax Orthodox Chess meets Symmetric Chess (two queens flanking the bigamous King in an Orthodox-type setup).

Upon the debut of Ajax Orthodox Chess in the 2009-10's Game Courier Tournament (#4): "An Introductory Semi-Potluck", Carlos Cetina commented:

"The additional Commoner moves to rooks, knights and bishops increases the complexity of the game in a manner so exquisite that immediately induces me to transfer the concept to the symmetric setup on a 9x8 board.

Jose: Would you like to try it? I bring forward a fantastic game! We could play it with or without dropping ministers, as you like.

Following Fergus's suggestion for naming the symmetric setup, I would name this new variant: Ajax Bigamous Chess."

Jose Carrillo accepted Carlos' challenge (games one & two), and a new symmetric variant was born!



Reverse Symmetry gives both players the same perspective of the board, of their own army as well as their opponent's army.

The Ajax Bigamous Chess opening setup is as follows:

King e1; Queens d1, f1; Rooks a1, i1; Knights b1, h1; Bishops c1, g1; Pawns a2, b2, c2, d2, e2, f2, g2, h2, i2.

King e8; Queens d8, f8; Rooks a8, i8; Knights b8, h8; Bishops c8, g8; Pawns a7, b7, c7, d7, e7, f7, g7, h7, i7.

Both White and Black Ajax Ministers start off the board at the beginning of the game.

While both Bishops start off on same-color squares, the fact that Ajax Bishops can switch colors by means of their orthogonal non-capturing 'Ajax' moves, there is no need for any special rule to Adjust or Convert the Bishops to the opposite color.

The game can be played with or without any Ajax Minister drops altogether, it's the players' choice.

It does not matter whether you have dark or light square on your corners at the start of the game.


Ajax Chess pieces inspired by the Man or Commoner from Courier Chess are used.

All regular minor chess pieces (Rook, Bishop and Knights) move as in Orthodox Chess, with the additional feature that they can also move (but not capture! see below) as Courier Chess' Man (or Commoner): one square in any arbitrary direction, just like a King:

This means that Rooks get an additional one-step diagonal move (Ferz), Bishops get an additional one-step orthogonal move (Wazir), and Knights get all Man (Commoner) one-step moves.

There is a catch though to this new "adopted" move to the Orthodox Chess pieces! They are not allowed to capture with their new "adopted" moves. So Rooks are not allowed to capture on their diagonal move, Bishops can't capture on their orthogonal moves and Knights are not allowed to capture on their one-square moves.

The additional "adopted" Commoner moves are intended to easily allow a Rook, Bishop and Knight to move to a new outpost where they can carry their orthodox attacks. They can also use their "adopted" moves to block an enemy attack.

The King and Queen do not get any additional "adopted" moves, as they already can reach all one-step squares just like a Courier Man.

The Ajax-Minister

The Minister is an additional major piece in the Ajax Chessmen set, which is like an enhanced Courier Man or Commoner that can move AND capture on it's one-step moves (just like a Man, circles in green above), and can also leap two-squares AND capture in any direction (Alfil + Dababah - circles in blue above). Therefore Ajax Ministers are able to capture on all 16 squares within their reach.


Over The Board, Ajax Ministers are represented by handmade Prime Ministers (King pieces without the Cross Crown).

Any other fairy pieces though (i.e. Seirawan Elephants as Mastodons), or checkers men, can be used to represent the Ajax Ministers OTB.

The Ajax Minister is the latest re-incarnation of a piece that has been known before as Pasha (Paulovits's Game by Istvan Paulovits - c.1890), Squire (Renniassance Chess by Eric V. Greenwood - 1980), Jumping General (Grand Shatranj) or Jumping King (Atlantean Barroom Shatranj) [both by Joe Joyce - 2006], and Mastodon or Mammoth (Mastodon and Mammoth Chess by Mats Winter 2006).

Ajax-Minister's Drops

Two Ajax-Minister's Drops are allowed per player on their first rank, per game. The Ministers must be dropped on any empty square on a player's first rank as their sole move in a turn; similar to dropping pieces in Shogi (Japanese Chess), except that the drops are limited to the first rank..

There is no restriction as to when (opening, middlegame or endgame) do players need to drop their Ministers, or even a requirement to drop them (players may play without any Ministers if they choose).

Players can only drop ONE Minister per turn and the drops may not capture enemy pieces on the same turn.

The Algebraic Notation for a Minister's drop is: (Mxx) including the parenthesis.


Pawns can play one or two squares in their initial move. They capture one square diagonally as in regular chess and may promote to any piece (Queen, Rook, Minister, Bishop or Knight) upon reaching their last rank.


The goal of the game is to checkmate the opponent's King, as in Orthodox Chess.

Rules for check, checkmate, stalemate, castling, en passant, 50-move draw and Threefold Repetition Draw are like in Orthodox Chess.


This table shows where the King and Rook end up and the notation for each type of castling.

White castles a-side or longb-castlingO-O-ObKb1, Rc1
White castles i-side or longh-castlingO-O-OhKh1, Rg1
Black castles a-side or longb-castlingO-O-ObKb8, Rc8
Black castles i-side or longh-castlingO-O-OhKh8, Rg8

Castling may only occur under the following conditions:

These rules have the following consequences:


Game Courier Preset

The Game Courier preset enforces all rules (including castling, en passant, check, checkmate and stalemate).

The Ministers start off the board (on the B and W files), and can be played right from there (W1 or W2 for White, B7 or B8 for Black) to their initial squares just as a regular Game Courier move.


Algebraic Notation: 10.(Mb1) (Mg8)
Game Courier Notation: 10.M W1-b1 m B7-g8

The moves above would drop the White W1-Minister to b1 (provided b1 was empty), and the Black B7-Minister to g8 (provided g8 was empty).

Game Courier Preset

Ajax Bigamous Chess Preset

Ajax Bigamous Chess Preset (without Ajax Minister drops)

Game Courier Logs

Game Courier Logs for Games of Ajax Bigamous Chess

To see actual games that have been played on-line, follow the link above.

Chess Variants by the Author:

Other Presets by the Author:

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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.

By Jose Carrillo.
Web page created: 2010-07-10. Web page last updated: 2010-07-10