Large Shogi variants

The large Shogi variants: Chess on a huge scale

Orthodox Chess is played on an 8x8 board, each player having 16 pieces of 6 different types. In the universe of Chess variants, this is actually quite small. Capablanca has proposed variants on 10x8 or 10x10, introducing two novel piece types. But this pales in comparison with some of the historic (many centuries old) variants of Japanese Chess (Shogi). To give you an idea: modern Shogi is played on a 9x9 board, with 2 x 20 pieces of 14 different types. And this is a minor modification of the historic 'Sho Shogi', meaning 'small Shogi'!

The number of piece types in Shogi tends to be large, because it is not only Pawns that promote in Shogi. Most other pieces promote as well. In contrast to western Chess, there is no promotion choice (other than whether you want to promote or not). Each piece type promotes to a specific other type, written on the bottom of the piece, so that promotion an be performed by flipping the piece. (Traditional Japanese pieces are flat pentagonal chips.) So the number of piece types in a Shogi game is close to double the number of piece types in the opening position. (Slightly less, because some pieces cannot promote.)

To quote a practical example: Chu Shogi ('middle Shogi'), one of the more popular Shogi variants, and before the invention of Crazyhouse-like piece drops actually the primary form of Chess in Japan is played on a 12x12 board, with 46 pieces of 21 different types in the initial position, 18 of which promote. Many of these promote to types that are already present in the initial setup, but these are not truly the same type (although they move the same), because the already promoted cannot promote a second time. So in total there are 36 different piece types, which move in 28 different ways.

Proliferation of piece types

And that was only for a 'middle' 12x12 game. The largest known variant, Taikyoku ('Ultimate') Shogi, is played on 36x36 with more than 200 piece types! You might wonder how the Japanese could dream up such an insanely large number of piece types. Yet most of these piece types do not have very special ways of moving: they almost all exclusively move along diagonals or orthogonals, and could thus said to be restricted versions of the Queen of orthodox Chess. It is just that their range of movement can be different in the various directions in an asymmetric way, and that other ranges than single steps or unlimited range (as the King and Queen in Chess, respectively) are possible. So there can be 'limited-range sliders' that move only upto 2, 3, 5 or 7 squares in a certain direction. By combining all these ranges you can get many piece types. For instance, a 'Golden Bird' can move upto 3 steps along any diagonal, 2 steps sideways, and slides any distance forward or backward. And a 'Left Chariot' can slide any distance straight forward, or along the left forward and right backward diagonal, and do a single step straight backward. And doesn't move at all in any of the other eight orthogonal/diagonal directions.

So most of the Shogi piece types are not very special at all, only differing from each other by how far they maximally slide in each direction. Chu Shogi is more regular than most, in this respect: the only ranges that do occur there are single steps or unlimited sliding moves. And all pieces are at least left-right symmetric. It would of course be an enormous task to memorize how several hundred pieces exactly move. But by using piece symbols that are indicative of the way of movement, this problem disappears completely. In fact this 'mnemonic piece set' makes it possible to play these games with almost no prior instruction.

Occasionally one encounters a piece that can jump to the second square, ignoring occupation of any other squares (i.e. a true leaper). In the mnemonic piece set such moves are indcated by a detached circle in the corresponding direction.

The pieces with moves that cannot be represented by the regular mnemonic system are mostly extremely strong pieces, with very special moves, which deserve special attention anyway, because the games often revolves around those. They are not very numerous at all. One concept pretty unique to the large Shogi variants are multiple moves: pieces that are allowed to do two or three stepping moves in a single turn. This is more than just a figure of speech to indicate they can reach squares not lying in any of the principal directions: they really can capture multiple opponent pieces in one turn. This is called 'Lion power', after the piece that exhibits this mode of moving in its purest and unrestricted form, a piece that occurs in all the large Shogi variants. A Lion can do one or two orthodox King moves per turn, and in addition is allowed to jump directly to any square that would be reachable that way on an empty board. (So this includes the Knight jumps of orthodox Chess, but also jumping orthogonally or diagonally to the second square.) It can move on for a second King step even if the first King step was a capture, making a second capture or moving on to an empty square, even withdrawing to its starting square. This means it also has the power to do a 'null move', moving to a neighboring empty square and back. (The picture above indicates the Lion moves in a Chu-Shogi position.)

The Lion, and three versions of it enhanced with other moves (Furious Fiend, Lion Hawk and Buddhist Spirit).

The Horned Falcon and Soaring Eagle have linear Lion power of two steps in a few directions, the Lion Dog and Teaching King of three steps in all directions.

Most of the small set of special pieces have such Lion power to a certain degree. Sometimes they simply combine the power to move as a Lion with some longer-range normal moves in some direction: The 'Furious Fiend' has a limited range of three in each of the eight directions, in addition to moving as a Lion, the Buddhist Spirit can even slide over unlimited distance in all eight directions (i.e. move as Queen or Lion). The 'Lion Hawk' moves as Bishop or Lion. Some pieces have Lion powers restricted to a certain direction. This means they can only make two steps along a given ray, not being allowed to change direction in between for stepping off the ray (but being allowed to step back along the ray, or jump directly to the second square). These are the 'Horned Falcon' (which only can do it in the forward direction, and slides along all other seven directions), and the 'Soaring Eagle' (which does it in the two diagonally forward directions, and slides in all others). The 'Lion Dog' is another piece that occurs in many of the larger Shogi variants; it is even allowed to do upto three single-step moves (capturing upto three pieces), but only along the same principal ray (i.e., the only changes in direction allowed between the steps are 180-degree turns, and it cannot 'overshoot' its starting square). Also here a number of initial steps can be replaced by a direct jump to that square. A 'Teaching King' combines the moves of a Lion Dog with that of a Queen. The 'Free Eagle' of Tenjiku Shogi has (in addition to moving as a Queen) Lion powers that are restricted in another way: it can do two steps, and change direction between them, but all these steps have to be diagonal steps.

Another type of special moves, encountered in the very large variants, are 'hook moves'. These are unlimited-range slider moves, where the trajectory is allowed to turn a 90-degree corner (once) at a point of the player's choosing. Pieces with such moves are enormously powerful: the 'Hook Mover', which can do such moves in all four orthogonal directions could reach any square on an empty board in a single move. (And because most squares could be reached in two ways, even on a sparsely populated board all squares could11:35 8-8-2012 be reachable. Other pieces with (diagonal) hook moves are the Capricorn, Goblin and Peacock. The latter only has hook moves along the forward diagonals, and a limited range of two steps along the backward diagonals. The other two have hook moves in all four diagonal directions, but the Goblin is also allowed to do single orthogonal steps, lifting the color binding from which the other diagonal hook movers suffer. Not all hook movers occur in all large variants, although the very largest variants tend to include 'every piece known to man'.

The Hook Mover, Capricorn, Goblin and Peacock have moves that can turn corners.

The large Shogi variants can be divided in three groups of closely related games:

Chu (middle) Shogi is basically a streamlined version of Dai (large) Shogi, leaving out the eight least-interesting piece types, and shrinking the board for faster play. It contains many detailed tweeks to its rules to make the game interesting (e.g. rules to prevent easy trading of Lions), and is clearly the most evolved of all the large Shogi variants. Tenjiku (exotic) Shogi is Chu extended with a 'zoo of weirdness', and might very well be the wildest Chess variant ever designed. (What to think about a 'Fire Demon', burning all opponents that stand next to it?)

In Group 2 Tai (grand) Shogi is basically a merger of Dai Dai (great great) Shogi and Maka Dai Dai (very great) Shogi. The latter two share many pieces, and include most of the Chu Shogi pieces (which all promote differently than in Chu Shogi, though). Promotion in these variants is different than in the Group-1 variants anyway: there is no promotion zone, but pieces promote when they capture. Promotion is often obligatory, and in many cases actually a demotion, as the promoted piece is much weaker. This really puts a new twist to tactics, where you have to think twice to even capture a hanging piece with something that heavily demotes, while exchanges that leave the last capture with a strongly promoting piece to the opponent should be frowned upon as well. Taikyoku (ultimate) Shogi is in a class of its own; it does not seem related to the other large variants, as pieces that move the same have often different names in Taikyoku and the others, while pieces that have the same name usually move differently.