Tryzantine Chess
by Charles Gilman
The etymology of this name may be degenerate but hopefully it conveys the theme, a three-handed form of Byzantine Chess. The one oddity is that there are only 21 ranks, lettered F to Z anticlockwise, rather than the 24 that you may expect and that I have since discovered are used in TriChezz. This makes colouring the board in just two colours impossible, but square colours are misleading anyway as no piece is conventionally colourbound if it goes far enough. Better to use Chaturanga patterning with marked King, Queen/Ferz, and Rook squares to keep track of where the three camps are. There are five choices between pairs of alternative rules, making 32 (25) different games, but in many cases the difference is slight. These do not include whether to put file A on the inside or outside, which has no material effect on the game. In all cases Rooks start on file A, Knights on file B, and Bishops or Elephants on file C. Listing armies in order of play ranks Y-G form the Red camp, K-N the Yellow camp, and R-U the Blue camp.
This first choice is between SIMPLE - Kings on DZ, DL, DS and Queens/Ferzes on DF, DM, DT - and KAMIL - Camels on file D and the "central" pairs on an extra file E.
The second choice is between ANCIENT - using Chaturanga pieces - and MODERN - using FIDE pieces. This has the usual effect on endgames, but also affects unbinding. Ancient gives the lifting of a much more restrictive binding by opening up the whole of files A and C (and E in combination with Kamil) to Elephants, but Modern allows Bishops to move between adjacent squares in only 8 moves, only 6 in combination with Kamil. In Modern a King that has not moved outside its own square and the neighbouring Queen/Ferz square may castle with a Rook on the same rank that has not moved outside the two Rook squares.
The third choice is between CYLINDER - the board's physical inner and outer edges are edges in play as well - and TORUS - pieces can move between the inner and outer ranks as if they were wrapped round into a torus. This has little impact on Simple Ancient but vastly strengthens Kamil Ancient by opening the whole board to Elephants. In combination with Modern it allows really long diagonal moves. With either Kamil it renders the sideways Knight and Camel moves identical!
The fourth choice is between UNIDIRECTIONAL - all Pawns move anticlockwise so that those on ranks Y, K, and R begin purely defensive - and BIDIRECTIONAL - all Pawns move away from their own camp towards the nearest enemy one. Only Pawns moving through their own camp have an optional double move, retaining it until they reach or pass their own army's other Pawn rank. Either way there is no capture en-passant.
The fifth choice is between FAST-PROMOTION - Pawns become other capturable array pieces at the first enemy marked rank they reach - and SLOW-PROMOTION - they become forward-only versions of array pieces there, becoming symmetric ones once they reach or pass the other enemy's back ranks. The forward-only pieces are the WING and MITRE of Constitutional Characters, the HELM and HUMP of From Ungulates Outwards, and the TUSK of The Heavy Brigade. Except for the Tusk, these pieces appear as array pieces in my Shogi variant Mitregi. A problem with Bidirectional Slow-promotion versions is the necessity to distinguish between half-promotees going in opposite directions!
Notes
When making enquiries as to whether this variant had been invented before I wondered whether anyone had thought of it for the 84-square contest. None had, but George Duke has since pointed out that there was an entry, Round Table 84, that had a round outer part of the board. That has a square-cell part in the centre and is a variant for only 2 players, but I do not wish to appear to slight even a tenuously related variant.