Many variants of shogi have been developed over the years, ranging from some of the largest chess-like games ever played, to some of the smallest. Some of these games are still regularly played, though none are currently anywhere near as popular as shogi itself. This article limits itself to those games which are native to Japan or derived from shogi.
It should be noted that the drop rule, often considered the most notable feature of shogi, is absent from most shogi variants, which therefore play more like other forms of chess, with the game tending to simplify as pieces are exchanged.
Predecessors of modern shogi
Some form of chess almost certainly reached Japan by the 9th century, if not earlier, but the earliest surviving Japanese description of the rules dates from the early 12th century (during the Heian period). Unfortunately, this description does not give enough information to actually play the game, but this has not stopped people attempting to reconstruct this early form of shogi, which is usually referred to as Heian shogi (平安将棋). Piece movements were as in modern shogi, but there was no rook or bishop. The board appears to have been 9x8 or 8x8. The setup is unknown, but can reasonably be assumed to have been the same as in modern shogi (minus the rook and bishop, and minus a gold general in the 8x8 case), although it's possible that the pawns started on the second rank rather than the third. It can safely be assumed that the game was played without drops.
By the 16th century the game had taken a form closer to the modern game: it was played on a 9x9 board with the same setup as in modern shogi except that an extra piece (a drunken elephant) stood in front of the king. This form of the game is known as sho shogi (小将棋), which means "little shogi". (While 9x9 may not seem 'little', it was smaller than the other shogi variants prevalent at the time.) The drunken elephant was eliminated by the Emperor Go-Nara (reigned 1526-1557), and it is assumed that the drop rule was introduced at about the same time, giving rise to shogi as we know it today.
There are a number of shogi variants played on boards larger than the standard 9x9. These variants are all quite old, and were probably all played without drops.
The same 12th century document which describes the Heian form of shogi also describes a variant played on a 13x13 board, which is now called Heian dai shogi (平安大将棋). As with the smaller Heian shogi, the rules for this game are not completely known.
The best known large-board variant is chu shogi (中将棋), played on an 12x12 board. The name means middle shogi, and the game is sometimes so called in English. Chu shogi has existed since at least the 14th century; there are even earlier references, but it's not clear that they refer to the game as we now know it. Chu shogi was still commonly played in Japan in the early 20th century, but has largely died out now. The game has, however, gained some adherents in the West. The main reference work in English is the Middle Shogi Manual by George Hodges.
Other large shogi variants are wa shogi (11x11, possibly played with drops), dai shogi (大将棋, "great shogi", 15x15), tenjiku shogi (天竺将棋, literally "Indian shogi", but probably meant in the sense of "exotic shogi", 16x16), dai-dai shogi (大大将棋, "great great shogi", 17x17), maka dai-dai shogi (マカ大大将棋, "ultra great great shogi", 19x19) and tai shogi (太将棋, "grand shogi", 25x25). All these variants go back to at least the 17th century. Tai shogi is often claimed to be the world's largest chess variant.
Tori shogi (鳥将棋 or 禽将棋, "bird shogi") dates from the late 18th century. The game is played on a 7x7 board and uses the drop rule. This is one of the more popular shogi variants.
Another comparitively popular variant is minishogi (5五将棋), which is played on a 5x5 board, but is otherwise the same as standard shogi. Judkin's shogi is similar, but has a 6x6 board.
Other modern variants include Kyoto shogi (京都将棋, 5x5), cannon shogi (9x9), micro shogi (4x5) and Christian Freeling's yari shogi (7x9).
- Shogi Variants program by Steve Evans (plays most of the variants mentioned in this article)
- American Chu Shogi Association (not only for Americans)
- International Chu Shogi Ladder (for play by e-mail games)
- Richard's Play-By-eMail Server (supports chu shogi, minishogi, tori shogi and yari shogi, amongst many other games)
- Rules for dimensionalized shogi on 2 boards (all the same rules, just the dimensional movement is added. The rules will be added here shortly. You can view the picture though. The name of the game, Shogi - The Next Generation)