Two players, Black and White (or 先手 sente and 後手 gote), play on a board ruled into a grid of 36 ranks (rows) by 36 files (columns) with a total of 1,296 squares. The squares are differentiated by marking or color.
Each player has a set of 402 wedge-shaped pieces of 207 types. The players must remember 253 sets of moves.
[...] Because the game was found only recently after centuries of obscurity, it is difficult to say exactly what all the rules were. Several documents describing the game have been found; however, there are differences between them. It is not too clear how accurate the rules given by modern sources for the game are, because many of the pieces appear in other shogi variants with a consistent move there, but are given different moves in taikyoku shogi. The board, and likewise the pieces, were made much smaller than usual for the other variants, making archeological finds difficult to decipher. Research into this game continues.
It is not clear if the game was ever played much historically.
the only video of it being played appears to have been a segment on a japanese trivia/comedy show where they recruited two professional shogi players to play it. the game ended after 32 hours and 41 minutes, and 3,805 moves.
they did not like it that much.
this brings us to the pawn of pawns, which is the most bizarrely overwrought set of game mechanics I have ever seen in maybe any board game.
when you promote the pawn of pawns the first time, it gets locked on the last rank like you're saving it for multiball on a pinball table. the next time your opponent is forked or otherwise forced to lose a piece to any of your pawns, the locked pawn is automatically dropped into a square that can attack one of the threatened pieces, even if that square is occupied (the occupying piece is removed from the game, even if it's yours), and it goes back to moving as normal.
... that is, until it gets to the final rank again, at which point it starts over by immediately moving to the starting square of the pawn of kings.
if you're anything like me, this immediately foreshadows something truly silly that happens the third time you promote it, and I'm happy to tell you that what happens is that this pawn -- which has now moved, like, 30 times minimum -- becomes the adventitious king, a special king that can move into his own citadel, permanently blocking his opponent from forcing a draw.
aside from the rules about the citadels and pawn promotion, Tamerlane chess honestly seems pretty reasonable, but the citadels and pawn promotion are absolutely nightmarish.
wikipedia helpfully describes it as "a restricted gryphon", which is I'm sure useful to at least one person on earth
the above is all great and excellent, and y'all should read it
but i just gotta add: so, reading the rules for tamerlane chess, i just assumed it was a 20th century chess variant. dear reader, no, no it is not. it's not a direct descendant of the western european chess game at all! it's a medieval variant of the ancient persian game of shatranj, which eventually led to western european chess. that is to say, tamerlane chess is western european chess's weird uncle