### 2.4 Shogi variants ¶

Several historical variants of shogi exist. Most of these were invented before modern shogi (in some cases hundreds of years before), are much larger than modern shogi and are not played with drops. Thus, in many ways they are really more like giant chess games than like modern shogi. The only one of these games to have survived in Japan is Chu (middle) shogi, which is still played a little bit. Thanks to the efforts of George Hodges and John Fairbairn of the Shogi Association (two British shogi enthusiasts), these games were resurrected and rules and sets for them can still be purchased from George Hodges (see References and links). I hope to eventually extend GNU shogi so that it can play at least some of these games. There are also several non-historical variants of shogi; I don’t know much about them but you can find information about them on the internet (see References and links).

The historical variants include:

1. Tori (bird) shogi, played on a 7x7 board with 32 pieces in all; this is the only variant that is known to have been played with drops.
2. Wa shogi, played on an 11x11 board with 54 pieces. This game can be played with or without drops but the historical evidence favors the view that it was played without drops. However, most people who have tried it claim it is a much better game with drops, being even more intricate than standard shogi.
3. Chu (middle) shogi, played on a 12x12 board with 92 pieces. This was (and is) by far the most popular of the variants, and has 21 different kinds of pieces in the starting line-up alone (along with several others that appear upon promotion). Unlike modern shogi, there are a tremendous number of ranging pieces and the game is definitely not played with drops. There is also an amazing piece called the Lion which has a double king move and can capture two pieces at once! Chu shogi has a small but fanatical following, some of whom consider it better than modern shogi.
4. Dai (great) shogi, played on a 15x15 board with 130 pieces. Other than the larger board, this game is very similar to Chu shogi.
5. Tenjiku (exotic) shogi, played on a 16x16 board with 176 pieces. This game is possibly the most complex tactical game in existence. There are many astoundingly powerful pieces, including one (the Fire Demon) that can capture up to eight opposing pieces in a single move! Despite the size of the game, checkmates can occur very suddenly (and often very early on) if one player makes a wrong move. Tenjiku also has a small but fanatical following, one of whom (Colin Adams) has written a book on the game which is available for download at http://wayback.archive.org/web/20120717085827/http://www.colina.demon.co.uk/tenjiku.html.
6. Dai-dai (great-great) shogi, played on a 17x17 board with 192 pieces. The opening setup alone has 64 different kinds of pieces! This game and the larger ones that follow sound pretty outlandish, but they have actually been played; a game of Dai-dai can supposedly be played in about 12 hours.
7. Maka-dai-dai (great-great-great) shogi, played on a 19x19 board with 192 pieces. For those for whom Dai-dai shogi is just too small :-)
8. Tai (grand) shogi, played on a 25x25 board with 354 pieces! Until recently, this was thought to be the biggest chess game ever devised, but now there is...
9. Kyoku tai (extremely grand?) shogi, played on a 36x36 board with 402 pieces. The rules for this have just been unearthed in an old Japanese book. Hopefully someone will soon organize a postal Kyoku tai shogi championship; maybe their distant ancestors could finish it :-)

   It is thought that the really huge games (Dai-dai and up) were never really played to any significant extent (gee, wonder why?) and were devised merely so that the creators could have the fun of inventing enormous games, amazing their friends and confounding their enemies. However, the games up to Tenjiku shogi at least appear to be quite playable, assuming one has the time.

Many modern variants have also been devised, usually on small boards, and often by western people. Those include:

1. Mini Shogi, played on a 5x5 board with 12 pieces. Its rules are nearly identical to Standard Shogi, and GNU Shogi has some support for it.
2. Judkins Shogi, similar to Mini Shogi on a 6x6 board.
3. Cannon Shogi, played on a 9x9 board, adds pieces inspired by the Cannon found in Xiang Qi (chinese chess)
4. Sannin Shogi, a 3-player variant on an hexagonal board, with specific rules governing alliance between two players
5. Kyoto Shogi, Micro Shogi, and several others are much more different.