Barsoomian Jetan

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Designed by Edgar Rice Burroughs, and made pyramidal by Carthoris Pyramidos
1922 original publication of Chessmen of Mars
Fantasy chess on Barsoom (Mars)
:Players Players: 2 - 2
:Time Length: Long?
:Complexity Complexity: High
Trios per color: (4)
Number of colors: 4
Pyramid trios:
Monochr. stashes: 4
Five-color sets: (4)
- - - - - - Other equipment - - - - - -
10x10 grid board
Setup time: 2 minutes
Playing time: 15 minutes
0.25 Hr
- 100 minutes
1.667 Hr
Strategy depth: High
Random chance: None
Game mechanics: chess, angular movement
Theme: Mars
BGG Link: Jetan
Status: complete? (v1.0), Year released: 2987


Jetan is the chess-like game played on Barsoom (i.e. Mars) in the John Carter adventures written by Edgar Rice Burroughs. This has historically led to some confusion with Martian Chess, which it is not. However, it is possible to play Jetan with pyramid pieces, and since Looney Pyramids are far more common than "proper" Jetan pieces, it might be that players could use the same pieces to become proficient in both kinds of "Martian Chess."

The standard (terrestrial) reference for Jetan is Chessmen of Mars (1922): most book reprints include an appendix outlining the rules.


Play alternates as in modern chess, with characterstic moves for each piece type, and captures made by moving into the space of the captured piece. Multiple pieces may not share a space.

Game resolution is as follows:

  • Victory -- One Chief captures the opposing Chief, OR
  • Victory -- Any piece captures the opposing Princess.
  • Draw -- Play continues for more than five moves by each player after both have been reduced to three or fewer pieces remaining, OR
  • Draw -- Either Chief is captured by a piece other than a Chief.

Practical experience suggests that Jetan is more playable if the second draw condition is abandoned, and the game is allowed to continue after the capture of the Chief by a non-Chief piece.

Pyramid Pieces for Jetan

Orange side Jetan pieces

Each side in Jetan has twenty pieces. Customarily, one side is black and the other is orange. The orange side is supposed to play from the north, where they represent the Yellow Martian people in their antagonism with the Black Martians from the south.

Jetan pieces may be conveniently constructed from four icehouse stashes: the side corresponding to Barsoomian orange with orange and yellow, and the Barsoomian black side with black and blue. In the following descriptions of individual pieces, the black-side pieces will be described; for the orange side, simply substitute orange for black and yellow for blue.


Eight (8) per side. Use four black and four blue icehouse pawns (1-pip pieces). The colors are a distinction without a difference in this particular case.

  • The Panthan piece as described by Burroughs has a single feather (symbol: f). It moves a single space straight or diagonally forward or to the side. Unlike all other pieces, it may not retreat. Unlike a pawn in modern chess, it is not promoted when it reaches the farthest rank of the board. The effect of this is that in a long game, surviving Panthans "patrol" the far rank after fully penetrating the opposite side.


Two (2) per side. Use black icehouse queens (3-pip pieces).

  • The Barsoomian Thoat piece shows a mounted warrior with two feathers (symbol: ffR). It moves one space orthogonally and one space diagonally in any direction. Unlike most Jetan pieces, it may jump over intervening pieces.


Two (2) per side. Use a black drone on top of a blue drone (2-pip pieces).

  • The Warrior is traditionally represented by a piece bearing a glyph representing two crossed feathers (symbol: X). It moves up to two spaces orthogonally, with cornering permitted. (So, effectively: Two spaces orthogonally or one space diagonally -- although the diagonal move requires that one of the orthogonally adjacent squares be open to permit passage.)


Two (2) per side. Use blue queens.

  • The Padwar glyph has two feathers uncrossed (symbol: ff). It moves up to two spaces diagonally, with cornering permitted. (See the note on Warrior movement. While the net effect of a cornering diagonal move is two spaces on a straight orthogonal path, the intermediate orthogonal square may be occupied, and one of the diagonal squares adjacent to it must be open.)


Two (2) per side. Use a black drone on top of a blue queen.

  • A Barsoomian Dwar piece shows three feathers uncrossed (symbol: fff). It moves up to three spaces orthogonally, with cornering permitted.


Two (2) per side. Use a blue drone on top of a black queen.

  • A Flier glyph shows a three-bladed propellor (symbol: Y). It moves up to three spaces diagonally, with cornering permitted.


One (1) per side. Use a blue pawn on top of a black drone on top of a blue queen.

  • A Barsoomian Chief piece shows a crown with ten jewels (symbol: W). He moves up to three spaces, diagonally or orthogonally, with cornering permitted.


One (1) per side. Use a black pawn on top of a blue drone on top of a black queen.

  • A Princess has a crown with a single jewel (symbol: A). She moves up to three spaces, diagonally orthogonally, with cornering permitted, and the ability to jump intervening pieces. Once per game, she may Escape with a single move of up to ten spaces. She may never move into a threatened square or an occupied one (i.e. she cannot capture).

The Four-Treehouse-Set Solution

The piece designs above are all well and good for emulating traditional Jetan. But they aren't very economical under the current conditions for buying Looney Pyramids. They only use sixty pieces total (four stashes worth), but they involve a combination of Rainbow and Xeno colors, with a full monochrome stash of each. It is nonetheless possible to build an attractive Jetan set roughly congruent with the above designs, using only four 15-piece Rainbow sets.

  • First, and most obviously, substitute red for orange.
  • Second, use the green pieces as follows:
    • Use green pawns on top, and green queens for the bases of the Chiefs and Princesses for both sides.
    • Make the Warriors out of a black drone on top of a green drone and a blue drone on top of a green drone. (On the north side, the top drones will be red and yellow.)

Obviously, the same basic approach will work with Xeno sets. Use the clear pieces as the fifth color (in place of green), and make the north side out of orange and white, the south out of purple and cyan.

Standard Jetan setup per Edgar Rice Burroughs

Board and Setup

The traditional Jetan board is a 10x10 square grid with alternating black and orange spaces. The arrangement of the pieces is as shown in the diagram at right.

As in modern chess, the pieces are initially set up in the two ranks closest to the player. The front rank consists of the eight Panthans, flanked by the two Thoats at the left and right edges of the board. The back rank has the two center squares occupied by the Chief and Princess, the Chief to the player's left. (Note: Unlike modern chess, the initial piece positions do not reflect perfectly across the central latitude of the board. The Princess will be in the same file as the opponent's Chief, and vice versa.) Outside of them, place the Fliers. Outside those are the Dwars. Outside those are the Padwars. And the Warriors are in the two corners.


Donkey Jetan Variant

Six of Eeyore's Chessboard wedges will create a board with 96 squares, nearly the full area of the 100-square Jetan grid. Jetan may be played on this hexagonal board, setting it up with outer corners towards the two players. The two squares on the central diagonal in the near corner are empty at setup, with the pieces otherwise distributed normally against the two near edges. Here is a picture of the variant setup as viewed by the black player:


The ideas of "forward" and "sideways" get a little twisted here, so Panthan movement is simply definable as being never towards the two near edges. Panthans at the "far rank" have an area of fifteen spaces (the entire two far edges) to patrol in Donkey Jetan, rather than merely ten as on the usual square 100-grid.

One effect of this starting arrangement is that it makes it possible for the Chief, Princess, and Fliers to be developed more quickly without disturbing the Panthan rank. (They can emerge on the central diagonal.) But the best strategy favors building a robust "Panthan skeleton" nevertheless.

In general, the two sides come into contact much more quickly: There are only eight spaces diagonally on the central axis between the two players, rather than the ten-space orthogonal distance from one side of the traditional Jetan board to the other. Creative use of the outer files can be important in this variant!

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