Tai shogi


Tai shogi is a large board variant of shogi. The game dates to the 15th century and is based on earlier large-board shogi games. Before the discovery of taikyoku shogi in 1997, tai shogi was believed to be the largest playable chess variant, if not board game, ever. One game may be played over several long sessions and require each player to make over a thousand moves. It was never a popular game; indeed, a single production of six game sets in the early 17th century was a notable event.
Like other large-board variants, but unlike standard shogi, the game is played without drops, and uses a promotion-by-capture rule.
Because of the terse and often incomplete wording of the historical sources for the large shogi variants, except for chu shogi and to a lesser extent dai shogi, the historical rules of tai shogi are not clear. Different sources often differ significantly in the moves attributed to the pieces, and the degree of contradiction 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.

Rules of the game

Tai shogi is essentially a merger of two other large-board shogi variants: dai dai shogi and maka dai dai shogi. Almost all the pieces of those two smaller games are included, and where the same pieces are found, they move the same way. Additionally, many of the tai shogi pieces not from those two games already appear in the even more popular chu shogi. 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.
The promotion rule is contested. Dai dai shogi and maka dai dai shogi have very different promotion rules. 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. However, the promotion rules given in English-language sources are similar to those of dai dai shogi: most pieces do not promote. Both agree that promotion is compulsory upon capture if the piece can promote.
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. However, in tai shogi non-promoting copies of those powerful pieces can be obtained by promoting some weak pieces.
The difference is unusual: in all smaller variants, Japanese Wikipedia agrees with the English-language sources on promotions, even though it does not always agree on the moves. There are additionally some confusions in the Japanese Wikipedia promotions: for example, the fragrant elephant is said to exist in tai shogi, but without a piece promoting into it. Because of this, the promotions from the English-language sources have been followed throughout this article, with alternatives given in the footnotes. That is, most pieces do not promote, and promotion is compulsory on capture.

Objective

The objective of the game is to capture the opponent's emperor and prince. When the last of these is captured, the game ends. There are no rules for check or checkmate; however, in practice a player resigns when checkmated.

Game equipment

Two players, Black and White, play on a board ruled into a grid of 25 ranks and 25 files, for a total of 625 squares. The squares are undifferentiated by marking or color.
Each player has a set of 177 wedge-shaped pieces of 93 types. In all, the players must remember 100 moves for these pieces. The pieces are of slightly different sizes. From largest to smallest they are:
Several of the English names were chosen to correspond to rough equivalents in Western chess, rather than as translations of the Japanese names.
Each piece has its name in the form of two kanji written on its face. On the reverse side of some pieces are one or two other characters, often in a different color ; this reverse side is turned up to indicate that the piece has been promoted during play. The pieces of the two sides do not differ in color, but instead each piece is shaped like a wedge, and faces forward, toward the opposing side. This shows who controls the piece during play.

Table of pieces

Listed here are the pieces of the game and, if they promote, which pieces they promote to.
Piece KanjiRōmajiPromotes to
Emperor天王 tennō—
Prince太子taishi—
Hook mover鉤行kōgyōGold general
Long-nosed goblin天狗tengu—
Capricorn*摩?makatsuGold general
Peacock孔雀kujaku—
Soaring eagle飛鷲hijū—
Horned falcon角鷹kakuō—
Queen奔王honnō—
Rushing bird行鳥gyōchōFree demon
Free demon 奔鬼honki—
Free dream-eater 奔獏honbaku—
Water buffalo水牛suigyūFree dream-eater
Flying ox飛牛higyū—
Soldier兵士heishi—
Dragon king龍王ryūō—
Dragon horse龍馬ryūme—
Lion獅子shishiFurious fiend
*Furious fiend奮迅funjin—
Racing chariot走車sōsha—
Rook飛車hishaGold general
Bishop角行kakugyōGold general
White horse白駒hokku—
Whale鯨鯢keigei—
Standard bearer前旗zenki—
Vermillion sparrow朱雀suzaku—
Turtle-snake玄武genbu—
Blue dragon青龍seiryū—
White tiger白虎byakko—
Right chariot右車usha—
Left chariot左車sasha—
Side dragon横龍ōryūGold general
Dove鳩槃kyūhan—
She-devil夜叉yashaGold general
Golden bird金翅kinshi—
Great dragon大龍dairyū—
White elephant白象hakuzō—
Lion dog狛犬komainuGreat elephant
*Great elephant大象taizō—
Wrestler力士rikishiGold general
Guardian of the Gods金剛kongōGold general
Buddhist devil羅刹rasetsuGold general
Golden deer金鹿konroku—
Silver hare銀兎ginto—
Fierce eagle猛鷲mōjū—
Old kite古鵄kotetsuLong-nosed goblin
Violent ox猛牛mōgyū—
Flying dragon飛龍hiryūGold general
Old rat老鼠rōsoWizard stork
*Wizard stork*仙鶴senkaku—
Enchanted badger変狸henriDove
Flying horse馬麟barinQueen
Prancing stag踊鹿yōrokuSquare mover
*Square mover方行hōgyō—
Violent bear猛熊mōyū—
Side mover横行ōgyōGold general
Vertical mover竪行shugyōGold general
Reverse chariot反車hensha—
Phoenix鳳凰hōōGolden bird
Kirin麒麟kirinGreat dragon
Poisonous snake毒蛇dokujaHook mover
Northern barbarian北狄hokutekiFragrant elephant
*Fragrant elephant香象kōzō—
Southern barbarian南蛮nanbanWhite elephant
Eastern barbarian東夷tōiLion
Western barbarian西戎seijūLion dog
Blind bear盲熊mōyū—
Drunken elephant醉象suizōPrince
Neighboring king近王kinnōStandard bearer
Blind tiger盲虎mōko—
Blind monkey盲猿mōenMountain witch
*Mountain witch山母sambo—
Ferocious leopard猛豹mōhyō—
Reclining dragon臥龍garyū—
Chinese cock淮鶏waikeiWizard stork
Old monkey古猿koen—
Evil wolf悪狼akurō—
Angry boar嗔猪shincho—
Cat sword猫刄myōjin—
Coiled serpent蟠蛇banja—
Deva提婆daibaTeaching king
*Teaching king教王kyōō—
Dark spirit無明mumyōBuddhist spirit
*Buddhist spirit法性hōsei—
Right general右将ushō—
Left general左将sashō—
Gold general金将kinshō—
Silver general銀将ginshō—
Copper general銅将dōshō—
Tile general瓦将gashō—
Iron general鉄将tesshō—
Wood general木将mokushō—
Stone general石将sekishō—
Earth general土将doshō—
Go-between仲人chūnin—
Knight桂馬keimaGold general
Howling dog*?犬kiken—
Donkey驢馬robaGold general
Ram's-head soldier羊兵yōhei—
Lance香車kyōsha—
Pawn歩兵fuhyō—