Chu shogi#Game equipment

The objective of the game is to capture the opponent's king and, if present, the prince, which counts as a second king. These two pieces are called "royal pieces", as the game is lost when a player is left without any of them. Alternatively, under the rules of the Japanese Chu Shogi Association, it suffices to capture all the opponent's other pieces, leaving a bare king or a bare prince, whereupon the player wins and the game ends early, provided that one's own king is not immediately bared or captured on the next move. Unlike standard shogi, pieces may not be dropped back into play after capture.

Two players alternate making a move, with Black moving first. (The pieces are not differentiated by color, but rather by facing of the pieces, with the "sharp" end pointed at the opponent; the traditional chess terms "Black" and "White" are only used to indicate who plays first, and to differentiate the sides during discussions of the game.) A move consists of moving a piece either to an empty square on the board or to a square occupied by an opposing piece, thus capturing that piece; and optionally of promoting the moving piece, if the move enters the promotion zone, or if it is a capture and any part of it is in the promotion zone.

Two players, Black and White (or {{lang|ja|先手}} {{lang|ja-latn|sente}} and {{lang|ja|後手}} {{lang|ja-latn|gote}}), play on a board ruled into a grid of 12 ranks (rows) and 12 files (columns), with a total of 144 squares. The squares are undifferentiated by marking or color, unlike a Western chess board.

Each player has a set of 46 pieces of 21 different types, and each piece has its name written on it in Japanese kanji. The writing is typically in black. On the reverse side of most pieces (i.e. except the king, queen, and lion) there are characters to indicate the piece's promoted rank, typically written in red. The pieces are wedge-shaped and their orientation indicates which player they belong to, as they point toward the opposing side. In all, the players must remember 28 moves for these pieces. The pieces are of slightly different sizes; from largest to smallest (most to least powerful) they are:

Image:Chu shogi initial setup.png on each piece.]]

• 1 King
• 1 Queen (also referred to as a "running/rushing/free king", which is a direct translation of the Japanese name)
• 1 Lion
• 2 Dragon kings
• 2 Dragon horses
• 2 Rooks
• 2 Bishops
• 1 Kirin (sometimes called "Kylin", an anglicisation)
• 1 Phoenix
• 1 Drunk elephant
• 2 Blind tigers
• 2 Ferocious leopards
• 2 Gold generals
• 2 Silver generals
• 2 Copper generals
• 2 Vertical movers
• 2 Side movers
• 2 Reverse chariots
• 2 Lances
• 2 Go-betweens
• 12 Pawns

Listed below are the pieces of the game and, if they promote, the pieces they promote to. Names are rough translations that have become somewhat standardized in English. Pieces are listed alphabetically by their English name.

The promotions apply only to pieces that start out with the ranks in the left-most column. That is, pieces with these ranks written in black; promoted pieces with those same ranks written in red may not be promoted further. Pieces that only appear upon promotion, that is, names that only occur written in red, are marked with an asterisk. The king, queen, and lion do not promote.

:¹ The pronunciations of {{Lang|ja|龍馬, 奔王, 反車}}, and {{Lang|ja|白駒}} are irregular. The regular forms {{Lang|ja-latn|ryūme, hon’ō, hansha,}} and {{Lang|ja-latn|hakuku}} are also seen.

:² The alternative pronunciations {{Lang|ja|盲虎}} {{Lang|ja-latn|mekura}}, {{Lang|ja|香車}} {{Lang|ja-latn|yari}}, {{Lang|ja|歩兵}} {{Lang|ja-latn|hohei}} or {{Lang|ja-latn|fu}}, and {{Lang|ja|鯨鯢}} {{Lang|ja-latn|geigei}} are also sometimes seen.

:³ Bishops, gold generals, and rooks arising from promotion (not the ones present initially) are sometimes given the alternate readings {{Lang|ja-latn|chorokaku}}, {{Lang|ja|と金}} {{Lang|ja-latn|tokin}}, and {{Lang|ja-latn|kinbisha}} respectively.

Below is a diagram showing the setup of the players' pieces. The board setup is symmetrical: the way one player sees their own pieces is the same way that the opposing player sees their pieces.

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In some contexts, one-letter abbreviations may be necessary. Those used in WinBoard are given in the second column of abbreviations.

Promoted pieces are notated by a + in front of the symbol; thus a white horse is +L, and a promoted gold (now a rook) is +G.

Sometimes the kirin is abbreviated Ky (for kylin), and the queen FK (for free king).

The promotion zone is the 'enemy camp', the farthest four ranks of the board, which are mostly occupied by the opposing player's pieces when the board is first set up. When a promotable piece enters the promotion zone from outside, or makes a capture starting within the promotion zone, it has the option of "promoting" to a more powerful rank. Promotion is not mandatory, and in some cases it may be beneficial to leave the piece unpromoted. (For example, the pawn, gold general, silver general, copper general, ferocious leopard, phoenix, kirin, vertical mover, side mover, and go-between all lose some of their powers upon promoting, so that there may be immediate tactical reasons for deferral, even though they all gain much more than they lose.) Promotion is permanent and promoted pieces may not revert to their original rank, nor promote a second time. If a piece is not promoted upon entering the promotion zone, then it may only promote by making a capture, or by exiting and reentering the zone. Pawns are an exception (see below).The Middle Shogi Manual allows pieces to regain their promotability after they move once without promoting. However, the Japanese Chu Shogi Association uses a different promotion rule, where a piece can only promote on a non-capture when it enters the zone. Once in the zone pieces can only promote on captures. There is strong evidence from historic mating problems that this has always been the rule in Japan.

Promotion is effected by turning the piece over after it moves, revealing the name of its promoted rank. Promoting a piece has the effect of changing how that piece moves. See below. For example, promoting a kirin turns it into a lion, and thereafter it behaves exactly like the original lion, even for the lion-trading rules. (Which can be a reason to defer promotion of a kirin.){{Cite web|url=http://hgm.nubati.net/MSM/ChuMatesB.html|title = MSM Errata B}} A rook obtained by promoting a gold differs from an original rook, though, in that the latter can still promote (to dragon king), while the former cannot.

If a pawn reaches the furthest rank, it gets a second opportunity to promote on a non-capture. (This is because the pawn can never leave the zone, and there is a legitimate reason to defer its promotion: a pawn can stand between two protected lions without allowing either player to trade them, which is something a promoted pawn – a gold general – cannot do.) No such exception exists or is needed for lances (the only other piece with no backward moves) as there is never any reason to defer promotion of a lance in the first place: therefore, a lance that reaches the furthest rank without promoting becomes an immobile "dead piece" ({{lang|ja|死に駒}}). This last-rank promotion of pawns can likewise be declined, leaving the pawn as an immobile "dead piece". (Unlike for lances, this might still be done with reason, again because of the lion-trading rules.)

According to Okazaki Shimei, the go-between can likewise promote on the furthest rank on a non-capture. In the past, the Japanese Chu Shogi Association used this rule, but later repealed it because the go-between can go backwards. Some of the new rules given by Okazaki and not present in the Edo-period texts seem to be late innovations in the history of chu shogi from the Showa period.{{Cite web|url=http://www.chushogi-renmei.com/kouza/rule_hosoku2004.htm|title = 補足ルールならびに説明}}

An opposing piece is captured by displacement: That is, if a piece moves to a square occupied by an opposing piece, the opposing piece is displaced and removed from the board. A piece cannot move to a square occupied by a friendly piece, that is, by another piece controlled by the moving player.

Each piece on the game moves in a characteristic pattern. Pieces move either orthogonally (that is, forward, backward, left, or right, 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 is the sole exception, in that it is not required to move in a straight line.

As stated earlier, this game is based on dai shogi and all of the pieces of this game can be found in dai shogi. The eight types of pieces that were removed were all rather weak and all promoted to gold generals. Furthermore, the larger board of dai shogi makes the slow-moving step movers even slower. All of this made for comparatively dull gameplay.

Many pieces are capable of several kinds of movement, with the type of movement most often depending on the direction in which they move. The movement categories are:

Some pieces move only one square at a time. If a friendly piece occupies an adjacent square, the moving piece may not move in that direction; if an opposing piece is there, it may be displaced and captured.

The step movers are the king, prince, drunk elephant, blind tigers, ferocious leopards, the generals, go-betweens, and the 12 pawns of each side. Only the king and prince can move in all eight directions. The king and prince are additionally considered royal pieces, as losing both of them loses the game. The Japanese Chu Shogi Association, in addition to separating out the king and prince, also considers the pawns and go-betweens as a separate class of 'pawns' ({{lang|ja|歩}}), while the remaining step movers are called 'small pieces' ({{lang|ja|小駒}}).

Several pieces can jump, that is, they can pass over any intervening piece, whether friend or foe, with no effect on either. These are the lion, the kirin, the phoenix, the horned falcon and the soaring eagle. Only the lion can jump in all directions.

Many pieces can move any number of empty squares along a straight orthogonal or diagonal line, limited only by the edge of the board. If an opposing piece intervenes, it may be captured by moving to that square and removing it from the board. A ranging piece must stop where it captures, and cannot bypass a piece that is in its way. 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.

The ranging pieces are the queen, dragon king, dragon horse, rook, bishop, vertical mover, side mover, reverse chariot, lance, and all those pieces which do not appear in the initial setup except the prince. Only the queen can range along all eight directions. The Japanese Chu Shogi Association further divides them into greater ({{lang|ja|大走り駒}}) and lesser ({{lang|ja|走り駒}}) ranging pieces: the greater ranging pieces are the queen, horned falcon, and soaring eagle, and the remainder are lesser ranging pieces.

The lion has a double-capture ability, called a 'lion move', as to a lesser extent do the soaring eagle and horned falcon (promoted dragon king and dragon horse). The details of these powerful moves are described for the lion below.

Following are diagrams that indicate the movement of each piece. Pieces are listed roughly in order, from front to back rows, with pieces making similar moves paired. Pieces with a grey heading start out in the game; those with a blue heading only appear on the board as a promoted piece. Betza's funny notation has been included in brackets for easier reference, with the extension that the notation xxxayyyK stands for an {{not a typo|xxxK}} move possibly followed by an yyyK 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. Square brackets are used to make it clear what operators the a modifier chains together: thus DaK would denote a dabbaba move followed by a king move, but D[aK] would denote a piece that can move as a dabbaba, or twice as a king. Use [crM] for the expression that could be reached and returned by moving as M.

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• Step

: The go-between steps one square directly forward or backward. (fbW)

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• Step

: The pawn can only step one square directly forward. Upon reaching the furthest rank of the board, it is trapped unless it promotes. (fW)

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| colspan="2" style="background:#E0E0E0;" | Side Mover {{lang|ja|横行}} {{lang|ja-latn|ōgyō}} (promotes to free boar)

| colspan="2" style="background:#E0E0E0;" | Vertical Mover {{lang|ja|竪行}} {{lang|ja-latn|shugyō}} (promotes to flying ox)

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• Range

: The side mover can move any number of free squares orthogonally sideways; or,

• Step

: It can step one square directly forward or backward. (WrlR)

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• Range

: The vertical mover can move any number of free squares orthogonally, either forward or backward; or,

• Step

: It can take one step directly sideways. (WfbR)

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| colspan="2" style="background:#E0E0E0;" | Bishop {{lang|ja|角行}} {{lang|ja-latn|kakugyō}} (promotes to dragon horse)

| colspan="2" style="background:#E0E0E0;" | Rook {{lang|ja|飛車}} {{lang|ja-latn|hisha}} (promotes to dragon king)

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• Range

: The bishop can move any number of free squares along any one of the four diagonals. (B)

:Because it cannot move orthogonally, an unpromoted bishop can only reach half the squares on the board.

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• Range

: The rook can move any number of free squares along any one of the four orthogonals. (R)

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| colspan="2" style="background:#E0E0E0;" | Dragon Horse {{lang|ja|龍馬}} {{lang|ja-latn|ryūma}} (promotes to horned falcon)

| colspan="2" style="background:#E0E0E0;" | Dragon King {{lang|ja|龍王}} {{lang|ja-latn|ryūō}} (promotes to soaring eagle)

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• Range

: The dragon horse can move any number of free squares along any one of the four diagonals; or,

• Step

: It can take one step in any direction. (WB)

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• Range

: The dragon king can move any number of free squares along any one of the four orthogonals; or,

• Step

: It can take one step in any direction. (FR)

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| colspan="2" style="background:#E0E0E0;" | Lance {{lang|ja|香車}} {{lang|ja-latn|kyōsha}} (promotes to white horse)

| colspan="2" style="background:#E0E0E0;" | Reverse Chariot {{lang|ja|反車}} {{lang|ja-latn|hensha}} (promotes to whale)

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• Range

: The lance can move any number of free squares directly forward. It cannot return and is trapped upon reaching the farthest row unless it promotes. (fR)

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• Ranging

: The reverse chariot can move any number of free squares directly forward or backward. (fbR)

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| colspan="2" style="background:#E0E0E0;" | Blind Tiger {{lang|ja|盲虎}} {{lang|ja-latn|mōko}} (promotes to flying stag)

| colspan="2" style="background:#E0E0E0;" | Ferocious Leopard {{lang|ja|猛豹}} {{lang|ja-latn|mōhyō}} (promotes to bishop)

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• Step

: The blind tiger can take one step in any direction except directly forward. (FrlbW)

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• Step

: The ferocious leopard can take one step to any of the three squares ahead or three squares behind it, but not directly to either side. (FfbW)

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| colspan="2" style="background:#E0E0E0;" | Copper General {{lang|ja|銅将}} {{lang|ja-latn|dōshō}} (promotes to side mover)

| colspan="2" style="background:#E0E0E0;" | Silver General {{lang|ja|銀将}} {{lang|ja-latn|ginshō}} (promotes to vertical mover)

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• Step

: The copper general can take one step to any of the three squares ahead of it, or else directly backward, giving it four possibilities. (fKbW)

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• Step

: The silver general can take one step diagonally, or else directly forward, giving it five possibilities. (FfW)

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| colspan="2" style="background:#E0E0E0;" | Gold General {{lang|ja|金将}} {{lang|ja-latn|kinshō}} (promotes to rook)

| colspan="2" style="background:#E0E0E0;" | Drunk Elephant {{lang|ja|酔象}} {{lang|ja-latn|suizō}} (promotes to prince)

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• Step

: The gold general can take one step orthogonally, or else one step diagonally forward, giving it six possibilities. (WfF)

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• The drunk elephant can take one step in any direction except directly backward. (FfrlW)

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| colspan="2" style="background:#E0E0E0;" | Kirin {{lang|ja|麒麟}} {{lang|ja-latn|kirin}} (promotes to lion)

| colspan="2" style="background:#E0E0E0;" | Phoenix {{lang|ja|鳳凰}} {{lang|ja-latn|hōō}} (promotes to queen)

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• Jump

: The kirin can jump to the second square in one of the four orthogonal directions. Or,

• Step

: It can take one step diagonally. (FD)

:Because of its unusual movement, an unpromoted kirin can only reach half the squares on the board.

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• Jump

: The phoenix can jump to the second square in one of the four diagonal directions. Or,

• Step

: It can take one step orthogonally. (WA)

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| colspan="2" style="background:#E0E0E0;" | Queen {{lang|ja|奔王}} {{lang|ja-latn|honnō}}

| colspan="2" style="background:#d0d0f0;" | Flying Stag {{lang|ja|飛鹿}} {{lang|ja-latn|hiroku}} (promoted blind tiger)

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• Range

: The queen can move any number of free squares in any of the eight orthogonal or diagonal directions. (Q)

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• Range

: The flying stag can move any number of free squares directly forward or backward; or,

• Step

: It can take one step in any direction. (fbRK)

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| colspan="2" style="background:#d0d0f0;" | Flying Ox {{lang|ja|飛牛}} {{lang|ja-latn|higyū}} (promoted vertical mover)

| colspan="2" style="background:#d0d0f0;" | Free Boar {{lang|ja|奔猪}} {{lang|ja-latn|honcho}} (promoted side mover)

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• Range

: The flying ox can move any number of free squares forwards, backwards, or diagonally, but not directly to the side. (fbRB)

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• Range

: The free boar can move any number of free squares diagonally or to the side, but not directly forward or backward. (rlRB)

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| colspan="2" style="background:#d0d0f0;" | Whale {{lang|ja|鯨鯢}} {{Lang|ja-latn|keigei}} (promoted reverse chariot)

| colspan="2" style="background:#d0d0f0;" | White Horse {{lang|ja|白駒}} {{lang|ja-latn|hakku}} (promoted lance)

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• Range

: The whale can move any number of free squares directly forwards, backwards, or along either rear diagonal. (fRbQ)

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• Range

: The white horse can move any number of free squares directly backwards, forwards, or along either forward diagonal. (fQbR)

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| colspan="2" style="background:#E0E0E0;" | King {{lang|ja|玉将}} {{lang|ja-latn|gyokushō}}, {{lang|ja|王将}} {{lang|ja-latn|ōshō}}

| colspan="2" style="background:#d0d0f0;" | Prince {{lang|ja|太子}} {{lang|ja-latn|taishi}} (promoted drunk elephant)

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• Step

: The king can take one step in any direction. (K)

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• Step

: The prince can take one step in any direction, like a king. (K)

:If a prince is in play, it must be captured along with the king.

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::The next three pieces have special movements that involve the ability to move and even capture twice per turn.

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• Range

: The horned falcon can move any number of free squares along a straight line in any direction except directly forwards.

• Lion move

: It can step or jump up to two squares along a line directly forward, potentially capturing two pieces. This power includes igui and skipping a turn (see "Lion"), but not moving off the orthogonal.

: Similarly to the lion, the horned falcon cannot skip a turn if the adjacent square directly in front is occupied, or falls off the edge of the board.(BrlbR[crfW]fD)

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• Range

: The soaring eagle can move any number of free squares along a straight line in any direction except the forward diagonals.

• Lion move

: It can step or jump up to two squares along either forward diagonal, potentially capturing two pieces. This power includes igui and skipping a turn (see "Lion"), but not moving off the diagonal.

: Similarly to the lion, the soaring eagle cannot skip a turn if both of the adjacent squares on the forward diagonals are occupied, or fall off the edge of the board. (RbB[crfF]fA)

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| colspan="4" style="background:#e0e0e0;" | Lion {{lang|ja|獅子}} {{lang|ja-latn|shishi}}

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• Area move/double capture

: The lion can take a step in any direction up to twice per turn. It can continue after a capture on the first step, potentially capturing two pieces per turn. It can change directions after the first step, so that it can reach the squares that a knight jumps to in Western chess.

By returning to its starting square with the second step, it can effectively capture a piece on an adjacent square without moving. This is called {{lang|ja|居喰い}} {{lang|ja-latn|igui}} 'stationary feeding'. It can step to an adjacent empty square and back without capturing anything; this leaves the board unchanged, effectively passing a turn ({{lang|ja|じっと}} {{lang|ja-latn|jitto}}). {{Lang|ja-latn|Jitto}} may prove useful in endgame situations; it is traditionally indicated by tapping the lion and leaving it in place.

• Jump

: The lion can jump anywhere that it could step to on an empty board; that is, anywhere within a distance of two squares, except for the square it started on. (Hence {{lang|ja-latn|jitto}} is only possible if at least one adjacent square is empty.) This is equivalent to jumping in any of the eight diagonal or orthogonal directions, or making any of the jumps of a knight in Western chess. (NAD[aK])

• Immunity from capture

: Capture of a lion is forbidden in situations where this would in general just trade two lions out of the game:

1. A lion cannot capture a non-adjacent other lion (i.e. on a "☆" square) when it could then be recaptured on the next move, unless it captures something substantial (i.e. other than pawn or go-between) together with the lion in a double capture. (Such a double capture is called {{lang|ja|付け喰い}} {{lang|ja-latn|tsukegui}} or {{lang|ja|喰添}} {{Lang|ja-latn|kuisoe}} "additional eating", and recapturing that lion is called {{lang|ja|獅子を撃つ}} {{lang|ja-latn|shishi o utsu}} 'shooting the lion'.)
2. A non-lion cannot capture a lion when in the immediately preceding move a lion was captured by a non-lion on another square. This also applies to "hit-and-run" captures by a soaring eagle or horned falcon. (In recent times this has been amended by the Okazaki rule, that such a counter-strike is allowed against a lion that is unprotected.) The stipulation "another square" means that if a kirin captures a lion, it can always be recaptured even if it had simultaneously promoted to lion.

:Historic rule descriptions explicitly discuss a case where recapture slides over the square evacuated by the capturing lion ({{lang|ja|たはかげ足}} 'hidden protector'; the equivalent situation in Western chess is called an X-ray attack). But they do not mention cases where a pawn or go-between taken together with a lion in a double capture affect the possibility to recapture, making it controversial whether the latter could be exceptions to the stated rule (1). Furthermore, it is generally assumed that the lion-capture rules do not apply recursively in case of multiple lions, so that hypothetical recaptures ruling out a capture would not have to obey those, just like they also would not have to keep their king out of check.

: Note that there is no difference between promoted kirins and lions as far as these rules are concerned.

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Below are eight examples of the lion-trading rules in action. In all examples below, the Black and White pieces are distinguished by colour, rather than their direction as they would be in a real game. (Black moves up the board.)