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This item is a game information page
It belongs to categories: Orthodox chess, 
It was last modified on: 2001-01-30
 Author: Larry L. Smith. Inventor: Edgar Rice Burroughs. The Game of Jetan. Extensive discussion of various versions of the rules of Jetan. (10x10, Cells: 100) [All Comments] [Add Comment or Rating]
Fredrik Ekman wrote on 2019-11-27 UTC

I love Larry Smith's analysis, as shown in this article, but I am not comfortable with his conclusion that all variants of jetan were created equal. In my own analysis of jetan, published at ERBzine, I would like to think that I have shown conclusively that most of the jetan variants can in fact be treated as apochryphal. In Smith's terminology, the following pieces should be treated as "correct":

Chained Panthan, Chained Thoat, Chained Warrior, Chained Padwar, Chained Dwar, Chained Flier, Chained Wild Chief, Brave Chained Wild Princess

A case could be made to use the Free Thoat in place of the Chained, and there is also an optional board set-up. But otherwise, Burroughs' rules emerge as pretty clear after a thorough analysis.

George Duke wrote on 2018-04-30 UTC

Raumschach had been invented the previous decade, and T. R. Dawson had devised Nightrider and Grasshopper and Canon.

Jetan is nearing 100 years old, a Martian variety of Chess on decimal board.  Edgar Rice Burroughs ran 'Chessmen of Mars'  in 'Argosy Weekly'  Jan.-Nov. 1921.  Then an inmate of Leavenworth Prison,* Elston Sweet, presented a carved piece set, and Burroughs added an Appendix to the first novel edition published 1922, explaining the rules better.  Larry Smith here gives further air to the possible different interpretations.  

In the story the game is played lifesize at the arena in Barsoonian location of Manator in a fight to the death.  In the surrounding culture Kaldanes are mostly brain, and Rykors headless bodies Kaldanes use as vehicles. 

Whichever combination of piece move rules are accepted, there are two-step movers and three-step movers, so no long-rangers -- befitting the science fiction hand to hand combat.  I hold interpretations of the Rules that give six of the eight piece-types multiple paths, two up to five as it turns out for different pieces, as sliders, bent and not, to arrival squares. It's not the approach Smith and Cazaux take, but it would seem to be vital how many ways each one has to get from departure to target.

Where can it go, and how does it get there? -- is more crucially pre-scientific.

Burroughs says teams are not obligated to wager in play, and Larry broaches the subject in detail for the first time, but it is left mostly for the future. That is, in what form Martian Chess will accommodate allowed wagering.

*While incarcerated in Atlanta Penitentiary socialist Eugene Debs garnered a million votes for President in 1920 -- while 'Chessmen' was running serially. At the Manator arena slaves and prisoners, including nobles, are the pieces.

donald henry wrote on 2014-06-12 UTCPoor ★
read the appendix of chessmen of mars as a strict text and the game plays great-pieces move how many he says and no less-you DO need all twenty pieces to start the game-thoats cant jump-combination movement is not so complicated, three spaces orthogonally north, south, east, west, or any combination of directions on a checkered board these should be easily found.
please just try it stricly FROM the appendix and you will see the problem is people playing it like chess and not like jetan the two are as differing as earth and mars in actuality. play it by the book and write if you come upon a problem that cant be drawn back to gameplay/philosophical difficulties-you'll be pleasantly rewarded!:)

George Duke wrote on 2010-07-07 UTC
This continues from Cazaux's Jetan article. Cazaux himself implicates the second older and original variant by Burroughs with clearly non-jumping Odwar. I saw it too in the text of 'Chessmen of Mars' separate from the two main sets of rules. Jetan is a literary CV that never polished clear-cut rules but did come rather close, and the job has to be finished for him. Non-jumping Flyer is superior, made fully multi-path by clear specific pathways along diagonals always three-step. Otherwise, if full leaper instead -- ignoring for now the yet other hybrid interpretation mixing both stepping and leaping -- Flyer/Odwar becomes plain tri-compound of Ferz (1,1), Camel (1,3) and (3,3), the latter which Gilman dredges from our problemist past as ''Tripper'' by ways of George Jeliss. There are no other destination squares. Jetan's best main-line formulation, attributable to Burroughs, reserves jumping to Princess and Thoat exclusively in the natural order of things (further justified in follow-up comment). The Odwar should not leap because the diagonal pathways are interesting in themselves and because those destinations combining Ferz, Camel, or Tripper are meaningless without the idea of three diagonal steps inclusive of them all. Any leaper to those grouped squares is inferior to other popular organizations of target squares, such as Gilman's duals as bi-compounds or Buffalo (Ca, Z, N) as tri-compound. The latter is aesthetic for instance because the squares are adjacent to themselves and away from the departure square. Particular Jetan Odwar leaping becomes on the same ordinary level of Canadian Omega Chess Champion as more or less arbitrary tri-compound. That jumper Flyer ruins his whole point of existence, because the player does not then regard the underlying structure in similarity of three required steps on the diagonals of 10x10.

Larry Smith wrote on 2005-02-27 UTC
For those who are truly interested, check out James Spratt's Jetan-Sarang.
 A really cool Jetan variant.  It offers a larger playing field and more

He has even sculpted some pieces for it and the 'standard' Jetan set. 
If you want to buy a set, drop him an e-mail.

In fact, his game inspired me to create Warlord Jetan.

Larry Smith wrote on 2005-02-27 UTC
No one is obligated to use wagers in Jetan.  But ERB did specifiy that
 wagers were a large part of this game.

Of course, the dynamics which Mark points out works both ways.  And
 wagering does bring the Chief-draw into value, rather than it being an
 un-desired outcome.

There is also supposed to be ten games played between the opponents.  But
 this does not prevent players from attempting a simple game.

Posted at the Yahoo! Jetan Group are a series of games played between
 Kerry Handscomb and myself using the simple wager system which I propose
 in this paper.  They demonstrate that the game is quite playable in this
 form, and even enjoyable.  We utilized several different interpretation of
 the pieces, and had little trouble prosecuting a good game with each.

Mark Thompson wrote on 2005-02-27 UTCGood ★★★★
One possible drawback to playing any CV with a wagering system based on
putting a price on each piece is that it seems it would make the game more
materialistic. One of the endearing features of Chess is that its focus on
the Kings makes spectacular sacrifices for the sake of achieving checkmate
worthwhile. But if the point of the game is to end with the greatest value
of pieces still on the board, I think this aspect will be lost. A player
who hopes to win would play conservatively, trying to keep his own pieces
on the board rather than let their value fall into the hands of his
opponent, while a player who fears losing would try to make exchanges,
thereby reducing the value of the ultimate prize for the winner.

For whatever it's worth, I proposed a variant called 'Contract Jetan'
in a letter to a 2001 issue of Abstract Games magazine, which went about
like this: In Contract Jetan, a player could propose in mid-game some rule
change that would make it more difficult for his opponent to win,
accompanied by a 'proffer' of some tokens that would be added to the
ante if the opponent accepts the dare. Such a proposal would probably be
made by the player in a weaker position. For example, 'You must win in
the next 15 moves or forfeit,' or 'My Thoat can only be captured by your
Warrior', etc. If the opponent accepts the rule change, the proffer is
added to the ante and the rule change is in effect. If the opponent
refuses, then the player who offered it has the option of 'buying out the
contract' as follows: from the proffer he removes a number of tokens equal
to the excess of value of the other player's army over his own, plus his
own Chief's value, and gives that to his opponent; then he adds the rest
of the proffer to the ante, and rotates the board half a turn. Then they
play on, but having reversed their roles, and with the proposed rule
change in effect.

This variant is played in an unpublished work that ERB left unfinished,
'Corporate Lawyers of Mars.'

Larry Smith wrote on 2005-02-27 UTC
If players use the Manatorian set-up, I suggest they try a game with Chained Chiefs. The restricted movement of this piece binds both of them within an identical pattern, and can result in a potential Chief-takes-Chief win.

Larry Smith wrote on 2005-02-27 UTC
For those who are interested, for in-depth discussions with other fans of
ERB's Jetan, you may wish to visited the Yahoo! Jetan Group.

Be sure to catch up on the previous postings.

Larry Smith wrote on 2005-02-27 UTC
That inconsistency of the initial board set-up has long been noted at the
original webpage from which this page was generated.  The 'standard'
form is noted as Barsoomian and the other is noted as Manatorian.

Most use the Barsoomian form, but there is no restriction for the
preference of the Manatorian.

This page might need to be updated.

Fergus Duniho wrote on 2005-02-27 UTC
</P>Well, I'll admit that I hadn't gone down far enough to see that you actually gave your own preferences regarding how the game should be played. Using your terms, let me list what I think is the authentic interpretation:</P> <P><B>Chained Panthan</B><BR> <B>Chained Warrior</B><BR> <B>Chained Padwar</B><BR> <B>Jump Thoat</B><BR> <B>Chained Dwar</B><BR> <B>Chained Flier (Odwar)</B><BR> <B>Chained Wild Chief</B><BR> <B>Brave Chained Wild Princess with Chained Wild Escape</B></P> <P>As it turns out, this differs from Jean-Louis Cazaux's interpretation on the matter of the Princess' escape. His interpretation is what you call Free Wild Escape.</P> <P>The interpretation I give here is what I think the most literal and authentic interpretation is, not necessarily what I think would make the best game. That is a matter I haven't given much thought to. This is not an expression of a preference concerning how Jetan should be played but an expression of a conclusion concerning what is the most accurate reading of how Burroughs intended Jetan to be played.</P>

Fergus Duniho wrote on 2005-02-27 UTC
<P>I just found an inconsistency in <I>The Chessmen of Mars</I> that your page doesn't mention. Both the sources you cite indicate that the Chiefs and Princesses do not go in the same files as their counterparts. Rather, each player has his Chief to the left of his Princess. Yet in the game between Gahan and U-Dor, U-Dor's first move is impossible with this setup. Burroughs writes:</P> <BLOCKQUOTE> U-Dor moved his Princess' Odwar three squares diagonally to the right, which placed the piece upon the Black Chief's Odwar's seventh. </BLOCKQUOTE> <P>Gahan was playing Black, and given the setup the sources seem to agree on, it would be impossible for Orange to move its Princess' Odwar to the Black Chief's Odwar's seventh. The only Odwar he could move there, given the presumed setup, would be the Chief's Odwar. But if the Chief and Princess were transposed, then this first move in the game would be legal.</P>

Larry Smith wrote on 2005-02-27 UTC
I will admit that this page is very extensive in its exploration of the
potential interpretation of the rules of Jetan.  It is based upon several
decades of play and many arguments with opponents.

But all the various rules on this page are based upon the writings of

Although Jean-Louis offers a single interpretation, it is no more
'authentic' than any other combination which might be derived.  It is
merely a personal preference, like the one which I give at the end of this

Fergus Duniho wrote on 2005-02-27 UTC

Although this page does a good job of enumerating different interpretations of how to play Jetan, it is not very helpful for anyone who just wishes to understand how Burroughs intended the game to be played. This page makes the task of divining the authentic rules seem impossible. But based on my own reading of the The Chessmen of Mars, it doesn't seem to be that difficult to figure out, and I find myself in agreement with Jean-Louis Cazaux on the other Jetan page over what the authentic rules are.

David Paulowich wrote on 2004-09-17 UTC
Jetan is a fascinating chess variant. I am used to Jens Markmann's Jetan.zrf, which uses the same (I think) rules as the Variant 'Chained Wild Jetan with Wild Thoats' in ChainedWildJetan.zrf from <p> The 'Jester' in Sidney LeVasseur's Kings Court variant moves the same as the Free Padwar, except that the Jester is allowed an initial Alfil-jump in the game. The Jester and Free Padwar appear to be the weakest 'multiple path' pieces used in chess variants.

George Duke wrote on 2004-09-17 UTCExcellent ★★★★★
Six of eight Jetan piece-types have multiple paths in both sets of rules in 'Chessmen of Mars', text and appendix, giving latter precedence as Burroughs' intended revision. In appendix Warrior moves two squares orthogonally with 90-degree change of direction allowed. So, Warrior's two-path squares are the diagonally adjacent ones, 'Ferz squares'. A second piece, Padwar moves two diagonal in any combination of directions. Therefore, when Padwar 'turns' 90 degrees, it is going to a two-path square. To CV researchers, Padwar multiple-, that is two-, path squares are 'Dabbabah squares'. Notice that Warrior's one-path squares and Padwar's two-way squares are the very same Dabbabah squares. Both types of arrival squares, one-way and two-way, can be blocked, but it takes at least two pieces (of either colour) so a two-way one. These are two of the six multiple-pathers in Jetan.

George Duke wrote on 2004-09-15 UTCExcellent ★★★★★
My recent Comments under 'Sissa' and 'Rose' pursue theme of multiple-pathway pieces, including Falcon, Sissa, Rose and Half-Rose so far. Jetan here has several pieces that move to a given square in more than one way: Thoat, Dwar, Flyer or Odwar, and Chief or Chieftain.

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