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This page is written by the game's inventor, donald henry.

Ninth-Ray Jetan

this game is meant to be a "circular chess" version of Jetan-the classic edgar rice burroughs chess variant appearing in his highly popular 1922 installment of the barsoom series' "the chessmen of mars". all the rules and piece movement for this game are identical to traditional jetan with the exception of the circular board and a few associated compensatory rules necessary to adapt the board to the game itself. DISCLAIMER: i would strongly urge anyone who is interested in this game to play and spread standard jetan first if they havent already as this article in itself relies on a somewhat predisposed knowledge of the base game. *that said-let's get weird!*


two teams-orange and black. orange starts on the northside of the board and black on the south. in this version(for the sheer ease of setup) the black team is started on the first and second rows (A-J,1&2) and the orange on the tenth and ninth.(A-J,10&9) the pieces are arranged as follows: FIRST ROW: (a1)warrior-(b1)padwar-(c1)dwar-(d1)odwar-(e1)chief-(f1)princess-(g1)odwar-(h1)dwar-(i1)padwar-(j1)warrior SECOND:(a2)thoat-(b2-i2)panthan(x8)-(j2)thoat(*example notation for black team) on the circular board this causes the pieces "warrior" and "thoat" to be in direct adjacent 'contact' with their enemy counterparts and meaning that the thoats on both sides can open the ball for casualties right away on two fronts and if done correctly can prevent a good deal of movement by the opposing team by behaving as a 'blocker.'


THE PIECES: In order, as they stand upon the board in the first row, from left to right of each player. Warrior: 2 feathers; 2 spaces straight in any direction or combination. Padwar: 2 feathers; 2 spaces diagonal in any direction or combination. Dwar: 3 feathers; 3 spaces straight in any direction or combination. Flier(Odwar): 3 bladed propellor; 3 spaces diagonal in any direction or combination; and may jump intervening pieces. Chief: Diadem with ten jewels; 3 spaces in any direction; straight or diagonal or combination. Princess: Diadem with one jewel; same as Chief, except may jump intervening pieces. *The Princess may not move onto a threatened square, nor may she take an opposing piece. She is entitled to one ten-space move at any time during the game. This move is called the escape. Flier(Odwar): See above. Dwar: See above. Padwar: See above. Warrior: See above. And in the second row from left to right: Thoat: Mounted warrior 2 feathers; 2 spaces, one straight and one diagonal in any direction. Panthans: (8 of them): 1 feather; 1 space, forward, side, or diagonal, but not backward. Thoat: See above. *note* in a certain barsoomian city-state "Manator" they have no knowledge of flying machines and they call the flier "Odwar"( and hereafter so do i) and he is synonymous with an earthling general. here is a quote from the book explaining my varied game etymology."Instead they call him who stands next to the Chief or Princess, Odwar. The piece has the same moves and power that the Flier has in the game."


since there is *for some reason* a good deal of belief among some that the jetan rules as they stand in the appendix of the chessmen of mars are flawed or unclear. i will go out of my way to make the statement that THIS version of the game-aside from the circular board and associated compensatory mechanisms-is played adhering to an absolutely strict interpretation of the appendix rules written by burroughs as it was meant to be the final authority on gameplay-the information presented in the story represents an imperfect and sparsely described gist of the game meant for literary entertainment purposes. after that he had been contacted by fans in a prison claiming to have adapted that info into a playable game-it was after this point in time that ERB refined his language regarding the rules of jetan and presented it as a playable game for those who care to try such things.-that said-Here are the rules of the game as they were intended to be observed by their creator: The game is won when any piece is placed on same square with opponent's Princess, or a Chief takes a Chief. 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 the game is not won in the ensuing ten moves, five apiece. Two pieces may not occupy the same square except in the final move of a game where 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. The moves explained. Straight moves mean due north, south, east, or west; diagonal moves mean northeast, southeast, southwest, or northwest. A Dwar might move straight north three spaces, or north one space and east two spaces, or any similar combination of straight moves, so long as he did not cross the same square twice in a single move. This example explains combination moves. 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. Gambling: 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.


on the circular board the layout is such that the twenty center spaces are triangular and meet in the middle of the board (as there is no intervening obstacle as in traditional circular chess). on every file (A through J) there are in the center rank two adjacent triangular spaces in row of the same color (the fifth and sixth of the ten ranks of any of the ten files). as this would make an orthogonal forward moving piece able to tread two spaces of the same color in a row,or have odwars capable of landing on an opposing colored spaces(...and we cant have that...) there is a built-in mechanism to compensate for this: a necessary directional bias dubbed: "The Ninth-Ray" *on mars, 'ninth ray'(one of two extra fictional light rays not visible on earth)is harnessed to create a breathable atmosphere for the otherwise doomed world, in keeping with this theme-the ninth ray as a 'skewing of directional perspective'-maintains as playable a game with mechanics of an otherwise inoperative and impractical board design* this directional bias would displace the piece movement across center spaces by one space to the left or right(clockwise or counter clockwise as decided before play)of the homochromatic space 180 degrees in opposition to it in the center ranks. *as each file's fifth and sixth ranks are homochromatic and this would alter the behavior of movement between the two above mentioned spaces-the players decide(in jetan it's traditionally through gambling) which way this 'skewing of directional perspective' will alter the potential movement of the pieces across the fifth and sixth ranks(clockwise or counter clockwise). *the skewing of directional perspective refers to the treatment of these "180 degree" homochromatic relationships within the center ranks as diagonal movements rather than orthogonal ones-offsetting the range of movement of the pieces -by one space-in the bias direction agreed upon before the beginning of play(clockwise or counterclockwise)* "The Ninth-Ray" though a constant in the mechanical nature of the board is only truly influential to piece movement when ANY PIECE: A) is on either the fifth or sixth rank of any file and traveling across the center of the board B)is planning to traverse the center of the board from any space in passing to another space C)whose range of influence extends across the center of the board --again this alteration offsets true orthogonal and diagonal movement and displaces it one space to the right or left(A.K.A.clockwise/counterclockwise)as decided before play. **the panthan for example can move sideways,forward and diagonally forward one space and though the way the piece moves remains the same, the unique nature of movement across the fifth and sixth ranks allows for new potential threat/safety scenarios from otherwise impossible positions. The Ninth Ray is essentially an intentional detour both to add variety to the game play and to repair the discrepancy generated by the mechanics of the board. Here are a few situations to explain the alterations to piece movement under both clockwise and counter-clockwise directional biases. EXAMPLE A: the above mentioned panthan at A-5 and under a clockwise directional bias would be able to threaten J-6 and B-5(sideways), A-6 and I-5(diagonally forward)and J-5(orthogonal forward) EXAMPLE B: another panthan moving orthogonally forward under a clockwise bias from C-5 would end up on B-6),(B-5 or D-5 moving sideways) and (C-6 or A-6 going diagonally forward) Example C: an odwar moving(of course)diagonally under a counterclockwise bias would go from H-8, G-7,F-6 and land at either f5 or h5) the ninth ray also plays into the mythology of the barsoom series in that they have two colors in their spectrum that do not exist on earth: Eighth and Ninth ray. The Ninth Ray when specially processed and mixed with the "Aether" of outer space mixes to create a functional atmosphere. -HENCE-the ninth ray creates the game's 'atmosphere'! -it is the only reason i bothered to try to add-on to the legacy of burrough's amazing game-i felt that homage could be paid and jetan deserved to have the natural progression of innovation and entropy observed (in regards to offspring and evolution) in it's many decades of static obscurity. ---Note: this game can also be played as a mortifying "Juggernaut" variant-using the same rules for traditional juggernaut chess in regards to the juggernaut's own movement and other conditions which are as follows: "The Juggernaut, as its name suggests, is a moving force of destruction. At the beginning of the game, you place the Juggernaut randomly on the board. (You can place it in one of the four central squares, if it makes you feel more secure; or you can roll for any coordinates but it shouldn't make much difference.) Then, after every move, you roll a ten-sided die to see which way the Juggernaut moves. Unfortunately for the hapless chessmen(of mars), the Juggernaut(on barsoom dubbed "The Colossus Of Yorn") is completely indestructible. Anything it touches, dies. It will wander merrily about the board, destroying everything in its path, until nothing is left. So why a ten-sided die? On a 1-8, the Juggernaut moves as follows: 8 1 2 7 J 3 6 5 4 If the die comes up 9, a momentary respite has been earned, and the colossus merely sits there, unmoving. On a 10(or zero), it teleports. *Roll the die two more times to pick a random rank and file.*the sole exception in this 'juggernaut-jetan' to earthling juggernaut behavior is that when ten or zero is rolled and when the coordinates are subsequently rolled for, a nine or ten/zero is not "re-rolled" as in standard juggernaut chess because jetan HAS a ninth and a ten rank and file! and due to this there are new draw conditions built in to compensate for the fact that there is a 2% chance the juggernaut may randomly teleport to the spaces occupied by a players chief or princess and in this circumstance of course there could be no winner and the game would be decided a draw.

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By donald henry.
Web page created: 2014-06-11. Web page last updated: 2014-06-11