at the arena in the Barsoomian location of Manator, with actual living people, who are dressed to appear the same as the pieces they represent. The game is a fight to the death, when a warrior is moved into one of the squares, and a warrior of the opposing color occupies the space, the two must engage in mortal combat. The game is intended to portray a battle between the Black Martians of the south and the Yellow Martians of the North and hence the board is traditionally orientated to these directions. While criminals and slaves are usually used as pieces, nobles also participate on occasions. It is played in Manator to win a beautiful woman, usually an exceptionally comely slave. It undoubtedly originates from Burrough's own fascination with Chess. The game rules mirror the structure and plot of the book, with a powerful hero (Gahan of Gathol/the Chief) who needs to rescue a beautiful damsel (Tara/the Princess) from a terrible villain (U-Dor/the opponent Chief). Burroughs also usually gives his hero a sidekick, and here there are two (the Odwars). The other pieces make up the anonymous hosts of allies and henchmen. On August 6, 1922 Burroughs received a letter from a prisoner, Elston B. Sweet, an inmate of Leavenworth Prison. Sweet and another inmate had used the references to Jetan in the pulp magazine to make a Jetan set, with carved pieces, after which they had played numerous games, and the game had become popular with other prisoners. Burroughs wrote back on August 16, 1922 to inform the pair they had created the first ever actual set. Interest in the game from fans was high; consequently, he included the rules in an appendix, entitled "Jetan, or Martian Chess", when the novel version was published. A chapter on the game was included in the 1968 book Chess Variations by John Gollon. Gollon made a Jetan set, curious about the game principally as a novelty and played with it; he was surprised by how much he enjoyed the game, and even described it as a 'respectable game'. The concept inspired imitation by authors of later planetary romances influenced by Burroughs, each of whom felt compelled to invent their own extraterrestrial version of chess to be fought with human beings. Instances of such homage include: Lin Carter's Darza, from Renegade of Callisto, 8th volume in his Callisto series Kenneth Bulmer's Jikaida, from