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Volume 7030a

The Rules of Jetan, or Martian Chess
By Edgar Rice Burroughs, edited by Fredrik Ekman
Part of the "Exploring Jetan" Feature at ERBzine 7030

The game of jetan was invented by Edgar Rice Burroughs for his novel The Chessmen of Mars (1922). This version of the rules has been edited in order to fix the most obvious ambiguities. Burroughs’ own words have been retained as far as possible.

The Board
Jetan is played on a square board consisting of one hundred alternate black and orange squares. On Mars the board is usually arranged so that the Black pieces are played from the south and the Orange from the north.

The Pieces
The game is played with twenty black pieces by one player and twenty orange by his opponent, and is presumed to have originally represented a battle between the Black race of the south and the Yellow race of the north.

The pieces follow. In order, as they stand upon the board on the first rank, from left to right as seen from each player.
Warrior: 2 feathers; 2 spaces orthogonal in any direction or combination.
Padwar: 2 feathers; 2 spaces diagonal in any direction or combination.
Dwar: 3 feathers; 3 spaces orthogonal in any direction or combination.
Flier: 3 bladed propellor; 3 spaces diagonal in any direction or combination; and may jump intervening pieces. (Option: The Flier may be replaced with the Odwar. The piece has the same moves and power that the Flier has and has five feathers.)
Chief: Diadem with ten jewels; 3 spaces in any direction; orthogonal or diagonal or combination.
Princess: Diadem with one jewel; same as Chief, except may jump intervening pieces.
Flier: See above.
Dwar: See above.
Padwar: See above.
Warrior: See above.

And on the second rank from left to right:
Thoat: Mounted warrior 2 feathers; 2 spaces, first one orthogonal and then one diagonal in any direction. (Option: The Thoat has three feathers and may jump intervening pieces.)
Panthans: (8 of them) 1 feather; 1 space, forward, side, or diagonal forward, but not backward or diagonal backward.
Thoat: See above.
(Option: The orange Chief and Princess may be set up in reverse positions, so as to achieve a vertically mirrored setup.)

Starting the Game
The first move may be decided in any way that is agreeable to both players; after the first game the winner of the preceding game moves first if he chooses, or may instruct his opponent to make the first move.

Conditions for Ending the Game
The game is won when any piece is placed on same square with the opponent’s Princess, or a Chief takes a Chief.

If one player is stalemated (cannot legally move any of his pieces), then the other player automatically gains the victory.

The game is drawn when either Chief is taken by a piece other than the opposing Chief, or when both sides are reduced to three pieces, or less, of equal value and including Chief and Princess, and the game is not won in the ensuing ten moves, five apiece.

The Moves Explained
Players take turns and each player makes one move for each turn. The player who is about to move may not opt to refrain from doing so.

A piece must move exactly its number of spaces, not less. For instance, a Padwar may not be moved only one single space. If a piece that cannot jump is blocked in all directions, it may not move at all.

Orthogonal moves mean due north, south, east, or west; diagonal moves mean northeast, southeast, southwest, or northwest.

A combination move may consist of any combination of orthogonal or diagonal moves that is allowed for that particular piece. This example explains combination moves: A Dwar might move orthogonal north three spaces, or north one space and east two spaces, or any similar combination of orthogonal moves. A piece that makes a combination move must not visit the same square twice in a single move, including the square where it started.

The Princess may not move onto a threatened square, nor may she capture an opposing piece. She may move through a threatened square on the condition that she does not remain there. A player may not make a move that would expose the Princess to a threat from a hostile piece, even if that move would otherwise win or draw the game. The Princess is entitled to one ten-space move at any time during the game, so that she can be placed upon any free and unthreatened square on the board. This move is called the escape.

Two pieces may not occupy the same square except in the final move of a game, when the Princess is taken.

When a player, moving properly and in order, places one of his pieces upon a square occupied by an opponent piece, the opponent piece is considered to have been killed and is removed from the game. (Option: Dice or some other rules for dueling can be applied, so that when a piece is moved to a square occupied by an opposing piece, the two battle to the death for possession of the square and the one that is successful advantages by the move.)

The exact same position of all pieces upon the board must not occur more than twice within twelve turns. If it happens a third time, the moving player must recall his move and make another. A player who forces the opponent into a position where no other move is possible except to create the third identical position, must also recall his move and make another.

The Martians gamble at jetan in several ways. Of course the outcome of the game indicates to whom the main stake belongs; but they also put a price upon the head of each piece, according to its value, and for each piece that a player loses he pays its value to his opponent.

Original text © 1922 by Edgar Rice Burroughs; Public Domain in the United States. Changes © 2007, 2019 by Fredrik Ekman. Free to copy and distribute, as long as the original source is credited.

The jetan graphics are copyright © 2001 by L. Lynn Smith. Used by permission. The diagrams were produced with the Zillions of Games software.

Click for full-size images

Roy G. Krenkel

Jetan Battle by Joe Jusko

Jetan Arena by Thomas Yeates

Back to the "Exploring Jetan" Feature
at ERBzine 7030


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