Tai shogi
One game may be played over several long sessions and require each player to make over a thousand moves.
Different sources often differ significantly in the moves attributed to the pieces, and the degree of contradiction (summarised below with the listing of most known alternative moves) is such that it is likely impossible to reconstruct the "true historical rules" with any degree of certainty, if there ever was such a thing.
It is not clear if the game was ever played much historically, as the few sets that were made seem to have been intended only for display.
Only nine extra pieces are added that do not appear in any smaller games – the peacock, soldier, vermillion sparrow, turtle-snake, side dragon, golden deer, silver hare, fierce eagle, and ram's-head soldier.
(Indeed, two of the Edo-era sources generally do not describe a piece for tai shogi if it exists in a smaller variant.)
The promotion rules given on the Japanese Wikipedia are similar to those of maka dai dai shogi: almost all pieces promote, but most to the lowly gold general, even if they are much more powerful; and many weak pieces turn into "free" versions of themselves (in which stepping moves are replaced by unlimited ranging moves in the same directions).
In maka dai dai shogi with its demotions, The Chess Variant Pages suggest that promotion is only compulsory when capturing a promoted piece, which seems more reasonable because otherwise the most powerful pieces would quickly disappear.
Two players, Black and White (or 先手 sente and 後手 gote), play on a board ruled into a grid of 25 ranks (rows) and 25 files (columns), for a total of 625 squares.
(Sometimes the queen is called the "free king", a direct translation of its Japanese name.
The queen could also be abbreviated FK (for free king) and the kirin as Ky (for kylin).
(The traditional terms 'black' and 'white' are used to differentiate the sides during discussion of the game, but are no longer literally descriptive.)
The step movers are the prince, drunk elephant, neighbor king, blind tiger, blind monkey, ferocious leopard, reclining dragon, Chinese cock, old monkey, evil wolf, the generals (except the wood general), angry boar, cat sword, coiled serpent, deva, dark spirit, go between, and the 25 pawns on each side.
Some pieces can move along a limited number (2, 3, or 5) of free (empty) squares along a straight line in certain directions.
These pieces are the water buffalo, standard bearer, vermillion sparrow, turtle-snake, blue dragon, white tiger, dove, she-devil, golden bird, great dragon, white elephant, lion dog, wrestler, Guardian of the Gods, Buddhist devil, golden deer, silver hare, fierce eagle, old kite, violent ox, flying dragon, old rat, enchanted badger, flying horse, prancing stag, violent bear, the barbarians, and the wood general.
Many pieces can move any number of empty squares along a straight line, limited only by the edge of the board.
If an opposing piece intervenes, it may be captured by moving to that square and removing it from the board.
The hook mover, long-nosed goblin, Capricorn, and peacock can move any number of squares along a straight line, as a normal ranging piece, but may also abruptly change tack left or right by 90° at any one place along the route, and then continue as a ranging piece.
Among the pieces that only appear with promotion, so do the teaching king, buddhist spirit, and furious fiend.
(Note that this situation is extremely theoretical anyway, because allowing both these powerful pieces to be captured at once would imply very poor play.
U denotes the universal leaper, a piece which can jump to any square on the board except the one that it is on.
As it finishes a capturing move, the lion dog promotes to a great elephant (above).
The wizard stork does not exist except as a promoted Chinese cock or old rat (below).
The wizard stork does not exist except as a promoted Chinese cock (above) or old rat (below).
Nothing promotes into a racing chariot, but it was included here due to the symmetry of its move with that of the square mover (right).
A player who captures the opponent's sole remaining king or prince wins the game.
In practice this rarely happens; a player will resign when loss is inevitable and the king will be taken on the opponent's next move (as in International Chess) because of the tradition that it is seen as an embarrassment to lose.
The very artificial situation of a smothered stalemate, where no moves are possible (even those that would expose the king), is not covered in the historical sources.
The method used in English-language texts to express shogi moves was established by George Hodges in 1976.
This is particularly significant for the hook mover and capricorn, which are two of the most powerful pieces in the game, but "promote" to the weak gold general; and the old kite and poisonous snake, which promote respectively to the hook mover and long-nosed goblin.
The first two are generally though not always in agreement, but the third differs in the case of most pieces which are not found in smaller shogi variants.
