Ko shogi

Kō shōgi (廣将棋 or 廣象棋 'wide (elephant) chess') is a large-board variant of shogi, or Japanese chess. The game dates back to the turn of the 18th century and is based on xiangqi and go as well as shogi. Credit for its invention has been given to Confucian scholar Ogyū Sorai.

Rules of the game

Unlike standard shogi, pieces may not be dropped back into play after being captured. Promotion rules are complex, and the fates of several pieces are interdependent.

Objective

The objective is to capture the opponent's commanding pieces: The general, plus the governor if present, or either the banner or middle army if not.

Game equipment

Two players, Black and White, play on a go board ruled into a grid of 19 "ranks" (rows) by 19 "files" (columns) with a total of 361 intersections.

Each player has a set of 90 pieces of 34 different types. The pieces are round and flattened like go stones. In all, the players must remember 65 different moves. The pieces are generally of the same size, though black pieces may be slightly larger than white pieces.

* 1 General
* 1 Clerk
* 1 Staff officer
* 2 Aids de camp
* 2 Sumo wrestlers
* 2 Aides
* 2 Staff
* 2 Chiefs of staff
* 2 Engineers
* 1 Taoist Priest
* 1 Spiritual monk
* 2 Advance guards
* 1 Middle troop
* 1 Drum
* 1 Banner
* 2 Sentries
* 2 Millenaries
* 2 Quartermasters
* 2 Centuriae
* 2 Rear guards
* 1 Gatling gun
* 6 Elephants
* 4 Long bows
* 4 Crossbows
* 4 Cannons
* 8 Cavalrymen
* 2 Cavalry
* 7 Pawns
* 2 Patrol units
* 7 Shields
* 2 Shield units
* 8 Chariots
* 2 Chariot units
* 1 Vanguard Each piece has its name in the form of one or two Japanese characters marked on its face, in white on black stones and in black on white stones. On the reverse side of most pieces are other characters in red; this side is turned up to indicate that the piece has been promoted during play.

Table of pieces

Listed below are the pieces of the game and, if they promote, which pieces they promote to. *Pieces marked with asterisks are not found at setup, and only appear with promotion. Many of the translations into English are suggestions only.

Game play

The players alternate making a move, with Black moving first. A move consists of moving a piece on the board and potentially capturing a piece or pieces and "promoting" a piece or pieces. Each of these options is detailed below.

Movement and capture

An opposing piece is generally captured by "displacement": That is, if a piece moves to an intersection occupied by an opposing piece, the opposing piece is displaced and removed from the board. A piece cannot move to an intersection occupied by a friendly piece (that is, a piece controlled by the same player). However, some shooting pieces are unable to capture by displacement, and therefore cannot move to an intersection occupied by an opposing piece.

Each piece in the game moves in a unique manner. Most pieces move in one of eight prime directions, 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, ×). At the beginning of the game the horse soldier is an exception in that it does not move in a prime direction. (The banner and drums, dragon ascending, war hawk, winged horse, and several other pieces are similar, but they only appear with promotion.)

Many pieces are capable of several kinds of movement, with the type of movement usually depending on the direction in which they move. The most common kinds of moves are "step", "range", "shoot", and "jump".

tep movers

Some pieces can move only one intersection at a time. (If a friendly piece, and sometimes an enemy piece, occupies an adjacent intersection, the moving piece may not move in that direction. Unlike in Go, 'adjacent' means any of eight intersections.)

The step movers at the beginning of the game are the general, aid de camp, aide, staff, chief of staff, engineer, middle troop, drum, banner, sentry, gatling gun, long bow, crossbow, shield, and pawn.

Limited range pieces

Some pieces can move along a limited number of free intersections along a straight line. Other than the limited distance, they move like range pieces (see below).

The limited range pieces at the beginning of the game are the chariot and the vanguard.

Jumping pieces

Several pieces can "jump", that is, they can pass over an intervening piece, whether friend or foe.

At the beginning of the game these are the clerk, staff officer, highway, spiritual monk, and cavalryman.

Range pieces

Many pieces can move any number of free intersections 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 intersection, and removing it from the board. A range piece must stop where it captures, and cannot bypass a piece 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 range pieces at the beginning of the game are the advance guard, millenary, quartermaster, centuria, rear guard, elephant, patrol unit, shield unit, and chariot unit.

hooting pieces

Some pieces can "shoot", that is, they can remove a piece from the board a limited distance from their location. Except for the cannon, they cannot shoot an enemy piece if another piece stands between the shooter and its target. The cannon, however, can shoot over such intervening pieces.

"It is not clear if a piece must move in order to shoot."

The shooting pieces are the highway, spiritual monk, gatling gun, long bow, crossbow, and cannon.

Burn

Wherever a burning piece arrives at an intersection, all adjacent enemy pieces are removed from the board, as described below.

The only burning piece is the poison flame, which only appears with promotion.

Multiple capture

The sumo wrestler and cavalry have double-move with double-capture abilities, similar to the 'lion move' in chu shogi. Unlike the lion, they are truly double-move pieces and do not have the ability to bypass a friendly piece occupying the first landing point. Unless stated otherwise below, the multiple moves do not need to be in the same direction and need not all be taken. A second or later move may return a piece to its starting location.

Among the promoted pieces, the master at arms, banner and drums, twelve-mile fog, thunderclap, roaming assault, dragon ascending, tiger wing, war hawk, and winged horse have multiple-capture abilities.

The gatling gun has a double-kill ability when it shoots.

Individual pieces

General 将 and middle troop 中軍
*Step: The general and middle troop can step one intersection in any direction, orthogonal or diagonal.

Clerk 記室
*Step: The clerk can step one intersection in one of the four diagonal directions.
*Jump: It can jump to the second intersection orthogonally.:"This is the move of the "kirin" in other shogi variants."

Staff officer 参謀
*Step: The staff officer can step one intersection in one of the four orthogonal directions.
*Jump: It can jump to the second intersection diagonally.:"This is the move of the "phoenix" in other shogi variants."

Aid de camp 親兵
*Step: The aid de camp can step one intersection in any direction, orthogonal or diagonal, except directly backward.:"This is equivalent to the drunk elephant in other shogi variants. However, it does not promote to a prince."

Sumo wrestler 力士
*Area move with double capture: The sumo wrestler "can" move in one turn as a general does in two.
**That is, it steps one intersection in any direction once "or" twice, potentially capturing two pieces per turn. By changing directions after its first step, so it can reach the intersections that a knight jumps to in Western chess.
**By moving back to its starting intersection, it can effectively capture a piece on an adjacent intersection without moving. This is called 居喰い "igui" "stationary feeding".
**A similar move without capturing leaves the board unchanged, which is a way to pass a turn.
*However, the sumo wrestler cannot jump over an intervening friendly piece as a "lion" can in other shogi variants.

Aide 舎人
*Step: The aide can step one intersection in one of the four orthogonal directions; or,
** One intersection diagonally forward, giving it six possibilities.:"This is the move of the gold general in other shogi variants."

Staff 舎餘
*Step: The staff can step one intersection in one of the four diagonal directions; or,
** One intersection straight forward, giving it five possibilities.:"This is the move of the silver general in other shogi variants."

Chief of staff 軍吏
* Step: The chief of staff can move one intersection in the four diagonal directions; or,
** It can move one intersection orthogonally forward or backward.:"This is the move of the leopard in other shogi variants."

Engineer 軍匠
*Step: The engineer can step one intersection directly forward or backward, or one intersection diagonally forward, giving it four possibilities.:"This is the move of the copper general in other shogi variants."

Taoist Priest 高道 and spiritual monk 神僧
*Jump: The Taoist priest and spiritual monk can jump to the second intersection in any direction, orthogonal or diagonal.
**However, they can only capture an enemy Taoist priest or spiritual monk with such a jump.
*Shot: They can shoot any one enemy piece on any intersection adjacent to their arrival point.:"These two pieces move and promote the same, but only the loss of the Taoist priest prevents or reverts promotion of the banner and drum."

Advance guard 前衛
*Range: The advance guard can move any number of free intersections directly forward; or,
*Step: It can step one intersection directly backwards.:"This piece promotes if its clerk promotes."

Drum 鼓 and Banner 旗
*Step: The drum and the banner can step one intersection in one of the four diagonal directions or either orthogonal sideways. That is, anywhere except directly forwards or backwards. :"These two pieces move and promote the same, but promote differently.":"If the drum is killed, the pawns may no longer move forward."

Sentry 護兵
*Step: The sentry can step one intersection in any direction except orthogonally forward.:"This is the move of the blind tiger in other shogi variants."

Millenary 千総
*Range: The millenary can move any number of free intersections along any one of the eight orthogonal or diagonal directions.:"This is the move of the free king in other shogi variants."

Quartermaster 把総
* Range: The quartermaster can move any number of free intersections along any of the four orthogonal directions; or,
* Step: It can move one intersection in any diagonal direction.:"This is the move of the dragon king in other shogi variants."

Centuria 百総
* Range: The centuria can move any number of free intersections along any of the four diagonal directions; or,
* Step: It can move one intersection in any orthogonal direction.:"This is the move of the dragon horse in other shogi variants."

Rear guard 後衛
*Range: The rear guard can move any number of free intersections directly backward; or,
*Step: It can step one intersection directly forwards. :"This piece promotes if its clerk promotes."

Gatling gun 佛狼機
*Step: The Gatling gun can move one intersection in one of the four diagonal directions. "It cannot capture by making such a move."
*Double shot: It can shoot two enemy pieces up to 7 free intersections from its landing point in any of the eight prime directions.
** It may shoot in different directions, or it may shoot one piece, and then shoot a second piece that had been blocked by the first.
**It cannot shoot a shield unit 牌総 or an imperial base 天塁. It can only shoot at a twelve-mile fog 五里霧 that is at least six intersections away.

Elephant 象
*Range: The elephant can move any number of free intersections along any of the four diagonal directions.:"This is the move of the bishop in other shogi variants."

Long bow 弓
*Step: The long bow can move one intersection in one of the four diagonal directions. "It cannot capture by making such a move."
*Shot: It can shoot one enemy piece up to three free intersections from its landing point, in any of the eight prime directions.
**It cannot shoot an imperial base 天塁, shield 牌, shield unit 牌総, chariot 車, chariot unit 車総, gun carriage 砲車, or twelve-mile fog 五里霧.

Crossbow 弩
*"The crossbow is identical to the long bow, except that it can shoot up to five free intersections away."

Cannon 砲
*Step: The cannon can move one intersection in one of the four diagonal directions. "It cannot capture by making such a move."
*Shot: It can shoot one enemy piece up to five free or occupied intersections away from its landing point in any of the eight prime directions.
**It cannot shoot an imperial base 天塁, shield unit 牌総, or twelve-mile fog 五里霧.

Cavalryman 馬兵
*Jump: The cavalryman jumps at an angle intermediate between orthogonal and diagonal, amounting to one intersection orthogonally plus one intersection diagonally, in a single motion, ignoring any intervening piece. That is, it has a choice of eight destinations.:"This is the move of the knight in Western chess.":"The horse soldier promotes if it captures a gatling gun."

Cavalry 騎総
*Double jump with double capture: The cavalry jumps once or twice as a horse soldier in a single turn, potentially capturing two pieces.
**If it jumps twice, both jumps must be in the same orthogonal direction (both forwards, backwards, to the left, or to the right). That is, after the cavalry makes its first jump, it is restricted to only two landing squares for its second jump, similar to the restriction of a knight in other shogi variants. Or,
**For its second jump, it may return to its starting point. This gives the cavalry a power of "igui" and passing a turn similar to that of the sumo wrestler.

Pawn 歩兵
*Step: The pawn can step one intersection in one of the four orthogonal directions. :"If the drum is captured, the pawns can no longer move in the forward direction."

Patrol unit 歩総
*Range: The patrol unit can move any number of free intersections orthogonally forward or backward; or,
*Step: It can step one intersection orthogonally sideways.:"This is the move of the vertical mover in other shogi variants."

Shield 牌
*Step: The shield can step one intersection in one of the four diagonal directions.:"The shield is unaffected by the bows" (弓,弩).

Shield unit 牌総
*Range: The shield unit can move any number of free intersections orthogonally to either side.
*Step: It can step one intersection in one of the four diagonal directions.:"The shield unit is unaffected by the bows" (弓,弩) "or the guns" (砲,佛狼機).

Chariot 車
*Limited range: The chariot can move one to five free intersections in one of the four orthogonal directions.:*It cannot capture the imperial base 天塁.:"The chariot unit is unaffected by the bows" (弓,弩).

Chariot unit 車総
*Range: The chariot unit can move any number of free intersections along any of the four orthogonal directions.:"This is the move of the rook in other shogi variants.":*It cannot capture the imperial base 天塁.:"The chariot unit is unaffected by the bows" (弓,弩).

Vanguard 先鋒
*Limited range: The vanguard can move one to five free intersections directly forward.

Promotion

Ko shogi has the most complex promotion rules of any shogi variant.

A player's "promotion zone" is the enemy camp, consisting of the six farthest ranks that comprise the opponent's territory at setup (the original line of the opponent's chariots and beyond). If a piece moves within this promotion zone, including moves into, out of, or wholly within the zone, then that player may "promote" the piece at the end of the turn. (The general, sumo wrestler, and elephant do not promote, nor do pieces which have already promoted.) Promotion has the effect of changing how a piece moves. See the table above for what each piece promotes to. Promotion is effected by turning the piece over, revealing the name of its promoted rank.

However, there are other ways of promoting than entering the enemy camp:

* A piece that captures a commanding piece (the general 将, governor 帥, middle troop 中軍, or banner 旗) promotes on the spot.
* A step mover (that is, a piece which can "only" move one step at a time) which captures a sumo wrestler 力士, dragon ascending 龍驤, roaming assault 招揺, or thunderclap 霹靂, promotes on the spot.
* The cavalryman 馬兵 promotes if it captures a gatling gun 佛狼機.
* When the clerk 記室 promotes to master at arms 軍師, the allied advance guard 前衛 and the rearguard 後衛 promote as well, while any enemy poison flame 毒火 dies. However, the clerk cannot promote by entering the promotion zone unless both the advance and rear guards have already entered the zone.

There are other circumstances that may prevent or revert promotion:

* If the Taoist priest 高道 is captured, the drum 鼓 and banner 旗 can no longer promote, and if either or both have already promoted (to roaming assault 招揺 or thunderclap 霹靂), then they immediately revert to drum or banner.
*Whenever the immaculate light 聖燈 is within 5 intersections of the twelve-mile fog 五里霧 along one of the eight prime directions, the fog reverts back to a Taoist priest 高道.

Many pieces only appear as a result of promotion. They are as follows:

Pieces that only appear with promotion

Master at arms 軍師 (promoted clerk 記室)
*Double move: Upon promotion, the clerk gains the power to move twice per turn. :"This is like a double kirin move in chu shogi and other shogi variants."

Banner and drums 旗鼓 (promoted staff officer 参謀)
*Double move: Upon promotion, the staff officer gains the power to move twice per turn. :"This is like a double phoenix move in other shogi variants."

Town brigade 千戸 (promoted aide 舎人)
*Range: The town brigade can move any number of free intersections directly forward or backward.
*Step: It can step one intersection in any direction.:"This is the move of the flying stag in chu shogi."

Village brigade 百戸 (promoted assistant 舎餘)
*Range: The village brigade can move any number of free intersections directly to either side.
*Step: It can step one intersection in any direction.

Vice commander 副司 (promoted chief of staff 軍吏)
* Range: The vice commander can move any number of free intersections along one of the four diagonal directions, or directly forward.

Poison flame 毒火 (promoted engineer 軍匠)
*Step: When it promotes, the engineer does not change how it moves, and it remains a step mover. However,
*Burn: Wherever it lands, all adjacent enemy pieces are 'burned' and removed from the board. :"It is not clear what happens when two opposing poison flames meet. Nor what happens if any other opposing piece lands next to a poison flame. See the "fire demon" in tenjiku shogi for some possibilities."

Twelve-mile fog 五里霧 and Immaculate light 聖燈 (promoted Taoist priest 高道 and spiritual monk 神僧)
*Double move: When they promote, the Taoist priest and spiritual monk gain the power to move twice per turn, including the option of shooting one adjacent piece after each move, and are still restricted from capturing by displacement.

*If a twelve-mile fog and immaculate light ever find themselves within 5 intersections of each other, the fog immediately reverts to a highway.
*The fog cannot be shot from within a distance of five intersections. It can only be shot (by the gatling gun 佛狼機) from a distance of six intersections or more.

Heaven’s vengeance (or 'Skyward net') 天網 (promoted advance guard 前衛)
* Range: The heaven’s vengeance can move any number of free intersections along either of the forward diagonals, or directly to either side; or,
* Step: It can step one intersection directly backward.

Governor 帥 (promoted middle troop 中軍)
*Step: The governor can step one intersection in any direction, orthogonal or diagonal.:"The governor functions as a second general."

Thunderclap 霹靂 (promoted drum 鼓)
*Areal quintuple move: The thunderclap steps five times per turn in an orthogonal direction, with the choice of changing directions after each step, potentially capturing up to five pieces.
**Unlike other multiple-move pieces, it must take all five steps. :"If the allied highway 高道 is killed, the thunderclap reverts to a drum."

Roaming assault 招揺 (promoted banner 旗)
*Limited-range quintuple move: The roaming assault can step "up to" five times per turn in any "one" orthogonal direction, potentially capturing up to five pieces.
**It cannot change direction while moving. :"If the allied highway 高道 is killed, the roaming assault reverts to a banner."

Dragon ascending 龍驤 (promoted millenary 千総)The dragon arising adds the moves of the sumo wrestler 力士 to those of the millenary.
*Double move: As the sumo wrestler, above. Or,
*Range: It can move any number of free intersections along any of the eight directions.

Tiger wing 虎翼 (promoted quartermaster 把総)
*Double move: The tiger wing moves like a shield (one step diagonally) once or twice per turn.

War hawk 鷹揚 (promoted centuria 百総)
*Double move: The war hawk can step one or two intersections in any orthogonal direction, potentially capturing a piece with each step. Or,
*Range: It can move any number of free intersections along any of the four diagonal directions.

Earth’s vengeance (or 'Earthward net') 地網 (promoted rear guard 後衛)
* Range: The earth’s vengeance can move any number of free intersections along either of the rear diagonals, or directly to either side; or,
* Step: It can step one intersection directly forward.

Chariot of the gods 神機車 (promoted gatling gun)
*Limited range: The chariot of the gods can move up to five free intersections along one of the four orthogonal directions.
**However, it cannot capture this way (that is, by displacement).
*Double shot: It retains the attack of the gatling gun: two pieces up to seven intersections away.

Longbow cavalryman 廣弓騎 (promoted long bow)The long bow cavalryman combines the move of the cavalryman with the attack of the long bow.
*Jump: It can jump as a cavalryman to any of its eight destinations.
**However, it cannot capture a piece this way.
*Shot: It can shoot one enemy piece up to three free intersections away from its landing point in any prime direction.

Crossbow cavalryman 弩騎 (promoted crossbow)The crossbow cavalryman combines the move of the cavalryman with the attack of the crossbow.
*Jump: It can jump as a cavalryman to any of its eight destinations.
**However, it cannot capture a piece this way.
*Shot: It can shoot one enemy piece up to five free intersections away from its landing point in any prime direction.

Gun carriage 砲車 (promoted cannon)
*Limited range: The gun carriage can move up to five free intersections along one of the four orthogonal directions;
**however, it cannot capture by displacement. Also,
*Shot: It can shoot as a cannon: One enemy piece up to five intersections away from its arrival point in any of the eight prime directions.
**Like a cannon, it can shoot over intervening pieces.
*The gun carriage cannot shoot an imperial base.
*It cannot be shot by a long bow or crossbow.

Winged horse 天馬 (promoted cavalry)
*Double move: The winged horse moves as a cavalry, but without any restriction on the direction of the second jump. That is, it moves twice like a knight in Western chess.

Commissar 都司 (promoted patrol unit 歩総 or vanguard 先鋒)
*Range: The commissar can move any number of free intersections along one of the four diagonals; or,
** It can move any number of free intersections orthogonally forward or backward.:"This is the move of the flying ox in chu shogi."

Imperial base 天塁 (promoted shield unit 牌総)
*Range: The imperial base can move any number of free intersections in the four diagonal directions, or directly to either side.:"This is the move of the free boar in chu shogi."
*The imperial base cannot be shot by the long bow 弓, crossbow 弩, cannon 砲, gun carriage 砲車, gatling gun 佛狼機, or chariot of the gods 神機車, nor can it be killed by the chariot 車 or chariot unit 車総.

Check and mate

Unlike Western chess, a player need not move out of check, and indeed may even move into check. Although obviously not often a good idea, a player with more than one commanding piece (general or governor) may occasionally sacrifice one of these pieces as part of a gambit.

A player is not allowed to give perpetual check to the sole objective piece.

Game end

A player who captures the opponent's general 将 and "either" the middle troop 中軍 "or" the banner 旗 wins the game. However, if the opponent's middle army has promoted to governor 帥, and the player captures the general and banner, then the governor takes command in place of the general and the game continues until it too is captured. That is, a player can continue the game with either the general, or the governor, or with both the middle troop and the banner together.

In practice the final capture rarely happens, as a player will resign when checkmated, as otherwise when loss is inevitable.

A player who makes an illegal move loses immediately. (This rule may be relaxed in casual games.)

Another possible, if rather 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 no contest. 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 tai shogi.

A typical example is P-8h.The first letter represents the piece moved (see above).Promoted pieces have a + added in front of the letter. (e.g., +MA for a governor (promoted middle troop). 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 intersection 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 25s being the bottom left corner. (This method of designating intersections is based on Japanese convention, which, however, uses Japanese numerals instead of letters. For example, the intersection 2c is denoted by 2三 in Japanese.)

If a piece captures by 'igui’ (possibilities are the sumo wrestler, dragon ascending, tiger wing, cavalry, winged horse, twelve-mile fog, immaculate light, banner and drums, or master at arms), the intersection of the piece being captured is used instead of the destination intersection, and it is preceded by the symbol '!'. If a second or later capture is made, then it is added after the preceding 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, MAx7c= indicates a middle troop capturing on 7c without promoting.

In cases where the above notation would be ambiguous as to which piece is meant, the designation of the starting intersection is added after the designation for the piece.

Moves are commonly numbered as in chess.

See also

* Shogi variant
* Whale shogi
* Hasami shogi
* Hand shogi
* Annan shogi
* Unashogi

External links

* [http://www.shogi.net/shogi.html Shogi Net]
* [http://history.chess.free.fr/koshogi.htm History.chess/Ko shogi]