Maka dai dai shogi

Maka dai dai shōgi (摩訶大大将棋 or 摩𩹄大大象戯 'ultra-huge chess') is a large board variant of shogi (Japanese chess). The game dates back to the 15th century and is based on dai dai shogi and the earlier dai shogi. The three Edo-era sources are not congruent in their descriptions of the pieces not found in smaller games. Apart from its size and number of pieces, the major difference from these smaller games is the "promotion by capture" rule. A more compact modern proposal for the game is called hishigata shogi.
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 (which were at some points of time the most prestigious forms of shogi being played), the historical rules of maka dai dai shogi are not clear. 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.
Rules of the game.
Objective.
The objective is to capture the opponent's king or emperor. If a prince is in play, it too must be captured. Unlike standard shogi, pieces may not be dropped back into play after being captured.
Game equipment.
Two players, Black and White (or "sente" and "gote"), play on a board composed of squares in a grid of 19 "ranks" (rows) by 19 "files" (columns) with a total of 361 squares. The squares are undifferentiated by marking or color.
Each player has a set of 96 wedge-shaped pieces of 50 different types. In all, the players must remember 74 different moves. The pieces are of slightly different sizes, from largest to smallest (or roughly most to least powerful) they are:
Many of the English-language names are chosen to correspond to their rough equivalents in Western chess, not necessarily as translations of the Japanese names.
Each piece has its name in the form of two Japanese characters marked on its face. On the reverse side of some pieces are one or two other characters, often in a different color (e.g., red instead of black); this reverse side is used 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 below are the pieces of the game and, if they promote, which pieces they promote to. Of the 50 kinds of pieces, 21 promote to gold, 26 promote to new pieces (though some move like starting pieces, "e.g." the free cat moves like a bishop, the free earth & goer like a reverse chariot); and 3 do not promote (queen, dragon king, and dragon horse). The new pieces are marked with an asterisk (*).
† The second character in 'wizard stork' is not present in most fonts: it should be 而 atop 鷦 ().
Setup.
Below is a diagram showing the setup of one player's pieces. The way one player sees their own pieces is the same way the opposing player will see their pieces.
The "Shōgi rokushu no zushiki" gives the following mnemonic poem to aid in the memorization of the initial setup:
Game play.
The players alternate making a move, with Black moving first. (The traditional terms 'black' and 'white' are used to differentiate the sides during discussion of the game, though the pieces are all the same color.) A move consists of moving a piece on the board and potentially "promoting" the piece. Each of these options is detailed below.
Movement and capture.
Most pieces in the game move in a unique manner.
Step movers.
The kings, drunken elephants, blind tigers, ferocious leopards, reclining dragons, Chinese cocks, old monkeys, evil wolves, generals, angry boars, cat swords, coiled serpents, dark spirits, Devas, go betweens and pawns only move one square at a time. If an opponent's piece occupies a square that is a possible destination for the moving piece, the opponent's piece may be "captured" by placing the moving piece on that square, and removing the opponent's piece from the board. If a friendly piece (that is, a piece controlled by the same player) occupies the square, the moving piece may not move in that direction.
Limited ranging pieces.
The lion dog, she-devil, wrestler, guardian of the Gods, Buddhist devil, violent ox, flying dragon and old rat can move along a limited number of free squares in certain directions.
Jumping pieces.
The lion, kirin, phoenix, donkey and knight "jump", that is, they can move over any intervening piece, whether friend or foe.
Ranging pieces.
The queen, dragon king, dragon horse, chariots, rook, bishop, side flier, movers and lance can move any number of squares along a straight line, limited by the edge of the board. If an opponent's piece intervenes, it may be captured by moving to that square, and removing it from the board. If a friendly piece intervenes, the moving piece is limited to a distance that stops short of the intervening piece; if the friendly piece is adjacent, it cannot move in that direction at all.
Hook moves (changing tack).
The hook mover and Capricorn can move any number of squares along a straight line, then any number of squares along a perpendicular straight line limited by the edge of the board. If an opponent's piece intervenes, it may be captured by moving to that square, and removing it from the board. If a friendly piece intervenes, the moving piece is limited to a distance that stops short of the intervening piece; if the friendly piece is adjacent, it cannot move in that direction at all. Although they have the ability to move in two directions in one move, they are not required to.
Promotion.
Pieces that can promote can choose whether or not they will promote when they capture an unpromoted enemy piece; however, if a piece captures a promoted piece, it must promote if able. Promotion is indicated by turning the piece over after it moves, revealing the character for the promoted piece. There are no promotion zones; dots on the board that usually represent promotion zones are present after the sixth rank only as a placement guide for initial setup.
Promoting a piece has the effect of changing how that piece moves.
Pieces which are already promoted cannot promote again, except as follows:
Any piece, promoted or not, that captures a Deva or teaching king (a promoted Deva) promotes to a teaching king. This is effected by replacing it on the board with the captured piece. Similarly, any piece that captures a dark spirit or Buddhist spirit (a promoted dark spirit) promotes to a Buddhist spirit. The only exception is (potentially) royal pieces (emperors, kings, princes, and drunk elephants) which promote to their normal promoted forms, or stay as they are if already promoted.
Otherwise, pieces don't promote more than once: they only have two sides.
Pieces on the 4th, 5th, and 6th ranks which promote, as well as the outside pieces of the 1st and 2nd ranks, promote (or perhaps demote) to Gold. Twelve of the pieces in the first and second ranks, as well as the go-between, become "free" when promoted, meaning that they move in the same directions as in their unpromoted state, but are free to move an unlimited number of squares in those directions. The remaining pieces gain entirely new powers when promoted.
Miscellaneous info.
The pawn, lance, stone general, iron general, and knight can only move forward. Therefore if one reaches the furthest rank (or the penultimate rank in the case of the knight), it is unable to move further, it must remain there until captured.
Pieces move either "orthogonally" (that is, forward, backward, or to the side, in the direction of one of the arms of a plus sign, +), or "diagonally" (in the direction of one of the arms of a multiplication sign, ×). The lion, knight, and furious fiend are exceptions.
Individual pieces.
In the diagrams below, the different types of moves are coded by symbol and by color: Blue for step moves, yellow for jumps, green for multiple capture, and pink for range moves, as follows: 
Piece names with a grey background are present at the start of the game; those with a blue background only appear with promotion. Betza's funny notation has been included in brackets for easier reference, with the extension that the notation "xxxayyyK stands for an "xxxK move possibly followed by an "yyy"K move, not necessarily in the same direction. By default continuation legs can go into all directions, but can be restricted to a single line by a modifier 'v' ("vertical", interpreted relative to the piece's current position on its path). The default modality of all legs is the ability to move and capture: other possibilities are specified explicitly. U denotes the "universal leaper", a piece which can jump to any square on the board except the one that it is on.
Check and mate.
When a player makes a move such that the opponent's king, emperor or prince (sole one in play) could be captured on the following move, the move is said to "give check" to the king, emperor or prince; the king, emperor or prince is said to be "in check". If a player's king, emperor or prince is in check and no legal move by that player will get the king, emperor or prince out of check, the checking move is also a "mate", and effectively wins the game. If a player has both a king (or emperor) and prince in play, then the player need not move only one out of check.
A player is not allowed to give perpetual check, or perpetually chase enemy pieces.
Game end.
A player who captures the opponent's king (or emperor, which is a promoted king) or prince (when the other is already gone) wins the game. In practice this rarely happens; a player will resign when loss is inevitable and the king (emperor) or prince 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.
A player who makes an illegal move loses immediately. (This rule may be relaxed in casual games.)
Another possible (but fairly uncommon) way for a game to end is repetition (sennichite). If the same position occurs four times with the same player to play, then the game is a draw. (Recall, however, the prohibition against perpetual check.)
Game notation.
The method used in English-language texts to express shogi moves was established by George Hodges in 1976. It is derived from the algebraic notation used for chess, but differs in several respects. Modifications have been made for maka dai dai shogi.
A typical example is P-8g.
The first letter represents the piece moved (see above).
Promoted pieces have a + added in front of the letter. (e.g., +OM for a mountain witch (promoted old monkey). The designation of the piece is followed by a symbol indicating the type of move: - for an ordinary move or x for a capture. Next is the designation for the square on which the piece lands. This consists of a number representing the file and a lowercase letter representing the rank, with 1a being the top right corner (as seen from Black's point of view) and 19s being the bottom left corner. (This method of designating squares is based on Japanese convention, which, however, uses Japanese numerals instead of letters. For example, the square 2c is denoted by 2三 in Japanese.)
If a lion captures by 'igūi’, the square of the piece being captured is used instead of the destination square, and this is preceded by the symbol '!'. If a double or triple capture is made, then it is added after the first capture.
If a move entitles the player to promote the piece, then a + is added to the end to signify that the promotion was taken, or an = to indicate that it was declined. For example, CSx7c= indicates a cat sword capturing on 7c without promoting.
In cases where the above notation would be ambiguous, the designation of the start square is added after the designation for the piece in order to make clear which piece is meant.
Moves are commonly numbered as in chess.
Hishigata shogi.
Sean Humby created a variant of maka dai dai shogi called Hishigata shogi. (See the external link below.) It was motivated by criticisms that maka dai dai takes a very long time to finish, and that the more interesting pieces have little opportunity for play. The only difference is in the setup, which places the opposing pieces close together and leaves the armies' rear flanks exposed, though Humby recommends that the teaching king be played as the weaker Western variant (as a queen), probably referring to the single alternative offered by Sean Evans' ShogiVar software, which is Queen plus 3-step King with full lion power, no longer believed to be the correct move by anyone.
Setup.
In the hishigata setup, only one rank is left empty between the opposing armies. This is indicated with a darker shading in the diagram below.
Maka dai shogi.
There are some minor attempts to revive maka dai dai shogi in Japan, with a few rule changes. This revived form of the game is called "maka dai shogi". The SZ and SSZ description of the furious fiend (lion + lion dog) is followed. The kirin and phoenix promote to the lion and queen, as in chu shogi. Promotion becomes mandatory on capture, but capturing a Deva or dark spirit does not result in promotion to teaching king or Buddhist spirit respectively. Only capturing the promoted forms of these pieces has that result. The blind bear's move is changed to FsW (one square in any direction but directly forward or backward), and the free bear no longer has the ability to make the forward diagonal jump (becoming simply BsR). The "free" pieces resulting from promotion have been changed to "ski-sliders" (skipping the first two squares before sliding, similar to the picket in Tamerlane chess), and many of the limited-range pieces have been changed to cannon-like hoppers that jump to the furthest square in their range, capturing any enemy pieces they leap over. The donkey loses its vertical stepping move and the knight has become a forward-only alfil. Many other minor changes are present: for example, the angry boar is now frlW and the old rat is fWbF.
Strategy.
Piece values.
According to the German Chu Shogi Association, the average values of the pieces are (using the interpretations of the English-language sources):
These average values do not take into account the special status of the king or prince as royal pieces, or the emperor as a disposable piece if other royals are present. They have also been normalized so that the pawn is worth 1 point to avoid fractions. Additionally, pieces change value if they have a good chance of promotion. This is particularly significant for the hook mover and capricorn, which are the two most powerful pieces in the game, but "promote" to the weak gold general.
Notes on pieces with conflicting descriptions.
These descriptions are taken from Japanese Wikipedia, which references the Edo-era publications 象戯図式 "Shōgi Zushiki" (SZ), 諸象戯図式 "Sho Shōgi Zushiki" (SSZ), and 象棋六種之図式 "Shōgi Rokushu no Zushiki" (SRZ). 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.