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Gyaku-sama Shogi

Introduction

Gyaku-sama Shogi (逆様組将棋 gyaku-sama shōgi, "reverse shogi") is inspired by H. G. Muller's Nutty Shogi and Hanten Shogi. The latter is probably one of the wildest games I have ever conceived. Hanten Shogi can is a bit intimidating, though, with 78 pieces of 36 types on a 16x16 board. Gyaku-sama Shogi is an attempt to shrink Hanten Shogi to a smaller game, with only 50 pieces of 25 types on a 13x13 board, without losing much of the original flavor of the original game.

Setup

Mitsugumi Shogi uses the same pieces as Suzumu Shogi and an initial position similar to that of Nutty Shogi. The only difference is that the Bishops and Rooks are transposed from their initial positions in Nutty Shogi, which leaves no pawn unprotected from normal captures. An interactive diagram has been provided (The Javascript source code was written by H. G. Muller) to make it easier to understand how each piece moves. The images used in the diagram and the table in the Pieces section are my own pieces, made using a free online pixel art drawing tool called Pixilart.

files=13 ranks=13 holdingsType=1 promoOffset=24 promoZone=0 maxPromote=22 promoChoice=+ graphicsDir=../membergraphics/MSribashi-shogi/ whitePrefix=w blackPrefix=b lightShade=#FFCC9C darkShade=#FFCC9C graphicsType=png squareSize=42 symmetry=rotate pawn:P:fW:p:a4-m4 dog:D:bFfW:d:d5,j5 knight:N:N:n:b1,l1 silver general:S:FfW:s:d1,j1 blind tiger:BT:FsbW:bt:f1,h1 ferocious leopard:FL:FvW:fl:c1,k1 gold general:G:WfF:g:e1,i1 lance:L:fRbW2:l:a1,m1 kirin:KY:FD:ky:c2 phoenix:PH:WA:ph:j2 vertical mover:VM:WvR:vm:a2,m2 bishop:B:B:b:c3,k3 side soldier:SS:WsRfnD:ss:a3,m3 rook:R:R:r:b3,l3 dragon horse:DH:BW:dh:d3,j3 dragon king:DK:RF:dk:e3,i3 chariot soldier:CS:BvRWnD:cs:d2 lion:LN:KNADcaKmcabK:ln:f2 queen:Q:Q:q:h2 bishop general:BG:pafpafcBmcBcpB:bg:f3 rook general:RG:pafpafcRmcRcpR:rg:g3 water buffalo:WB:BsRWnD:wb:k2 vice general:VG:pafpafcBmcBcpBKaKaaKmabK:vg:h3 fire demon:FD:BsRKaKaaKmabKcavKcafmafKmafcavK:fd:g2 tokin:+P:WfF:p2: multi general:+D:bBfR:d2: side soldier:+N:WsRfnD:n2: vertical mover:+S:WvR:s2: flying stag:+BT:KvR:bt2: bishop:+FL:B:fl2: rook:+G:R:g2: white horse:+L:fBvR:l2: lion:+KY:KNADcaKmcabK:ky2: queen:+PH:Q:ph2: flying ox:+VM:BvR:vm2: dragon horse:+B:BW:b2: water buffalo:+SS:BsRWnD:ss2: dragon king:+R:RF:r2: horned falcon:+DH:BbsRfWfDfcavWfmabW:dh2: soaring eagle:+DK:RbBfFfAfcavFfmabF:dk2: heavenly tetrarch:+CS:jsR3jBjvRcabK:cs2: lion hawk:+LN:BWNADcaKmcabK:ln2: free eagle:+Q:QADcasFcafFmcabF:q2: vice general:+BG:pafpafcBmcBcpBKaKaaKmabK:bg2: great general:+RG:pafpafcQmcQcpQ:rg2: fire demon:+WB:BsRKaKaaKmabKcavKcafmafKmafcavK:wb2: king:K:K:k:g1

Only the location of the pieces of one side are mentioned below, in normal (Chess-like) coordinates. The setup for the other side can be obtained by rotating the board 180 degrees. XBetza notation is included for easier reference.

First rank

  • a1, m1 Lance (fRbW2)
  • b1, l1 Knight (N)
  • c1, k1 Ferocious Leopard (FvW)
  • d1, j1 Silver General (FfW)
  • e1, i1 Gold General (WfF)
  • f1, h1 Blind Tiger (FbsW)
  • g1 King (K)

Second rank

  • a2, m2 Vertical Mover (WvR)
  • c2 Kirin (FD)
  • d2 Chariot Soldier (BvRWnD)
  • f2 Lion (KNADcaKmcabK)
  • g2 Fire Demon (BsRKaKaaKmabKcavKcafmafKmafcavK)
  • h2 Queen (Q)
  • j2 Phoenix (WA)
  • k2 Water Buffalo (BsRWnD)

Third rank

  • a3, m3 Side Soldier (WsRfnD)
  • b3, l3 Rook (R)
  • c3, k3 Bishop (B)
  • d3, j3 Dragon Horse (BW)
  • e3, i3 Dragon King (RF)
  • f3 Bishop General (pafpafcBmcBcpB)
  • g3 Rook General (pafpafcRmcRcpR)
  • h3 Vice General (pafpafcBmcBcpBKaKaaKmabK)

Fourth and fifth rank

  • a4-m4 Pawns (fW)
  • d5, j5 Dog (bFfW)

Pieces

The move of pieces from the initial setup is already given in Betza notation above, and should also be clear from the mnemonic piece glyphs in the image above. The Betza notation move of the piece types that can only be obtained through promotion is given below.

  • Great General (pafpafcQmcQcpQ)
  • Lion Hawk (BWNADcaKmcabK)
  • Free Eagle (QADcasFcafFmcabF)
  • Soaring Eagle (RbBfFfAfcavFfmabF)
  • Horned Falcon (BbsRfWfDfcavWfmabW)
  • Heavenly Tetrarch (jsR3jBjvRcabK)
  • Flying Ox (BvR)
  • White Horse (fBvR)
  • Flying Stag (KvR)
  • Multi General (bBfR)

The pieces in the table are the same pieces used in the interactive diagram above.

Piece Promoted Piece

King
The King moves one space in any direction.

The King can move into check at any time, although this is almost always a blunder.

The King does not promote.

Fire Demon

The Fire Demon can slide sideways or diagonally, or make an 'area move' - up to 3 King steps in independently chosen directions, stopping at the first capture. In addition, it has a unique multi-capturing ability known as a 'demon move' or 'demon power' - it can step up to three times along a straight line in any one of the eight orthogonal or diagonal directions, capturing up to two pieces. This power includes igui and skipping a turn, but not jumping or moving off the orthogonal or diagonal (See "Lion"). That is, when making a demon move, the Fire Demon can do the following:

  • It can capture a piece on the first square and then continue to the second or third square (the latter only if the second square is empty), capturing up to two pieces. Or it can capture an adjacent piece without moving as in normal igui. (Note however that it cannot then continue in the opposite directiion: it is restricted to one orthogonal or diagonal.)
  • If the first square is empty, it can capture a piece on the second square and then retreat to the first square or continue to the third square, capturing up to two pieces.
  • It is not required to make both moves.
The Fire Demon does not promote.

Vice General
The Vice General moves as a Bishop but can jump up to two pieces along the line of attack when taking. In addition, it can make an 'area move' - up to 3 King steps in independently chosen directions, stopping at the first capture. It can skip a turn, but it does not have the lion power of igui. The Vice General does not promote.
Water Buffalo The Water Buffalo can slide sideways or diagonally. In addition, it can slide one or two squares vertically. Fire Demon

The Fire Demon can slide sideways or diagonally, or make an 'area move' - up to 3 King steps in independently chosen directions, stopping at the first capture. In addition, it has a unique multi-capturing ability known as a 'demon move' or 'demon power' - it can step up to three times along a straight line in any one of the eight orthogonal or diagonal directions, capturing up to two pieces. This power includes igui and skipping a turn, but not jumping or moving off the orthogonal or diagonal (See "Lion"). That is, when making a demon move, the Fire Demon can do the following:

  • It can capture a piece on the first square and then continue to the second or third square (the latter only if the second square is empty), capturing up to two pieces. Or it can capture an adjacent piece without moving as in normal igui. (Note however that it cannot then continue in the opposite directiion: it is restricted to one orthogonal or diagonal.)
  • If the first square is empty, it can capture a piece on the second square and then retreat to the first square or continue to the third square, capturing up to two pieces.
  • It is not required to make both moves.
Rook General The Rook General moves as a Rook but can jump up to two pieces along the line of attack when taking. Great General

The Great General moves as a Queen but can jump up to two pieces along the line of attack when taking.

Bishop General The Bishop General moves as a Bishop but can jump up to two pieces along the line of attack when taking. Vice General

The Vice General moves as a Bishop but can jump up to two pieces along the line of attack when taking. In addition, it can make an 'area move' - up to 3 King steps in independently chosen directions, stopping at the first capture. It can skip a turn, but it does not have the lion power of igui.

Lion

The Lion has a special movement ability commonly called a 'lion move' or 'lion power'. It can make up to 2 King steps per turn, changing direction between them, even when this returns it to its starting square. it can make the first step as a jump, when it chooses to do so. So it can:

  • Jump directly to any square in the 5x5 area surrounding it,
  • Capture any adjacent piece without moving (igui),
  • Capture a piece on an adjacent square, and then continue to any of the squares adjacent to that square, capturing up to two pieces (this is equivalent to 2 turns for a King),
  • Stay in place without capturing anything if at least one adjacent square is empty, effectively passing a turn
Lion Hawk

The Lion Hawk moves either as a Bishop or as a Lion. This power includes jumping, igui and skipping a turn.

Queen

The Queen moves as it does in Chess - it slides orthogonally or diagonally.

Free Eagle

The Free Eagle moves as a Queen. In addition, it can move one square in any diagonal direction twice. This power includes jumping, igui and skipping a turn (see "Lion"). So it can:

  • Jump directly to any square in the second square in any direction,
  • Capture any diagonally adjacent piece without moving (igui),
  • Capture a piece on a diagonally adjacent square, and then continue to any of the squares diagonally adjacent to that square, capturing up to two pieces (this is equivalent to 2 turns for a Ferz),
  • Stay in place without capturing anything if at least one diagonally adjacent square is empty, effectively passing a turn
Chariot Soldier

The Chariot Soldier can slide vertically or diagonally. In addition, it can slide one or two squares sideways.

Heavenly Tetrarch

The Heavenly Tetrarch can slide diagonally or vertically. In addition, it can move two or three squares orthogonally sideways. In addition, it can capture pieces on adjacent squares without moving (igui).

It cannot move to any adjacent square, and is not blocked from moving by pieces on those squares. However, it is not a range jumper and cannot jump a piece anywhere else in its path.

Dragon King

The Dragon King moves as it does in Shogi - it can move as a Rook or as a King.

Soaring Eagle

The Soaring Eagle can slide orthogonally or diagonally backward. In addition, It can step twice, or jump two squares, diagonally forward, capturing up to two pieces. This power includes igui and skipping a turn, but not moving off the diagonal. (see "Lion").

Dragon Horse

The Dragon Horse moves as it does in Shogi - it can move as a Bishop or as a King.

Horned Falcon

The Horned Falcon can slide diagonally, sideways, or directly backward. In addition, It can step twice, or jump two squares, directly forward, capturing up to two pieces. This power includes igui and skipping a turn, but not moving off the orthogonal. (see "Lion").

Rook

The Rook moves as it does in Chess - it slides orthogonally.

Dragon King

The Dragon King moves as it does in Shogi - it can move as a Rook or as a King.

Bishop

The Bishop moves as it does in Chess - it slides diagonally.

Dragon Horse

The Dragon Horse moves as it does in Shogi - it can move as a Bishop or as a King.

Side Soldier

The Side Soldier can slide sideways or move one square directly backward. In addition, it can slide one or two squares directly forward.

Water Buffalo

The Water Buffalo can slide sideways or diagonally. In addition, it can slide one or two squares vertically.

Vertical Mover

The Vertical Mover can slide vertically or move one square sideways.

Flying Ox

The Flying Ox can slide vertically or diagonally.

Phoenix

The Phoenix can move one square orthogonally or jump two squares diagonally.

Queen

The Queen moves as it does in Chess - it slides orthogonally or diagonally.

Kirin

The Kirin can move one square diagonally or jump two squares orthogonally.

Lion

The Lion has a special movement ability commonly called a 'lion move' or 'lion power'. It can make up to 2 King steps per turn, changing direction between them, even when this returns it to its starting square. it can make the first step as a jump, when it chooses to do so. So it can:

  • Jump directly to any square in the 5x5 area surrounding it,
  • Capture any adjacent piece without moving (igui),
  • Capture a piece on an adjacent square, and then continue to any of the squares adjacent to that square, capturing up to two pieces (this is equivalent to 2 turns for a King),
  • Stay in place without capturing anything if at least one adjacent square is empty, effectively passing a turn
Knight

The Knight moves as it does in Chess - it moves to the nearest square that a queen cannot.

Side Soldier

The Side Soldier can slide sideways or move one square directly backward. In addition, it can slide one or two squares directly forward.

Lance

The Lance slides forward or up to two squares directly backward.

White Horse

The White Horse can slide vertically or diagonally forward.

Blind Tiger

The Blind Tiger moves as a King except directly forward.

Flying Stag

The Flying Stag moves as a King or slides vertically.

Ferocious Leopard

The Ferocious Leopard moves one square diagonally or vertically.

Bishop

The Bishop moves as it does in Chess - it slides diagonally.

Gold General

The Gold General moves as it does in Shogi - it moves one square orthogonally or diagonally forward.

Rook

The Rook moves as it does in Chess - it slides orthogonally.

Silver General

The Silver General moves as it does in Shogi - it moves one square diagonally or directly forward.

Vertical Mover

The Vertical Mover can slide vertically or move one square sideways.

Dog

The Dog moves one square orthogonally forward or diagonally backward.

Multi General

The Multi General slides orthogonally forward or diagonally backward.

Pawn

The Pawn moves as it does in Shogi - one square orthogonally forward.

Tokin

The Tokin moves as it does in Shogi - it moves one square orthogonally or diagonally forward.

Rules

Deciding who moves first

furigoma (振り駒 piece toss) is used to decide who moves first. One of the players tosses five pawns. If the number of tokins (promoted pawns, と) facing up is higher than unpromoted Pawns (歩), then the player who tossed the pawns plays Gote (後手 White) (that is, getting the second move).

The players may also decide who goes first through a game of chance or a mutual agreement.

Sente (先手 Black) moves first, then players alternate making a move. Making a move is required – skipping a move is illegal, even when having to move is detrimental. Play continues until a player's last remaining royal piece is captured, a player resigns, or a draw is declared.

Skipping a turn

The Fire Demon, Vice General, Lion Hawk, Free Eagle, Lion, Soaring Eagle, and Horned Falcon have the ability to skip a turn if at least one adjacent square is empty. (The Free Eagle can only do this on the squares diagonally adjacent to it, the Horned Falcon can only do this on the square directly in front of it, and the Soaring Eagle can only do this on either of the two squares diagonally in front of it.) However, it is illegal for a player to skip a turn more than three consecutive times. That is, a player is not allowed to perpetually skip a turn.

Promoting pieces that skip a turn inside the promotion zone do not have the option of promoting on that turn.

Promotion

Whenever a piece captures something, it promotes. Promotion is indicated by turning the piece over after it moves, revealing the character of the promoted piece. When a promoted piece captures, it demotes - that is, it is flipped back over to show its original unpromoted value. Promotion and demotion are mandatory - it is illegal to defer the promotion or demotion of a piece that has just captured, even when having to do so is detrimental. It is also illegal to promote or demote a piece without capturing, with the following exception:

When a Pawn reaches the last rank, it may promote even on a non-capture. This is because Pawns cannot move backwards or to the sides, and would otherwise have no legal move on subsequent turns. This last-rank promotion of Pawns can likewise be declined, leaving the Pawn as an immobile "dead piece" (死に駒 shi ni koma). However, if a Pawn captures something on the last rank, it must promote without exception.

The pieces promote as follows:

  • Water Buffalo <-> Fire Demon
  • Lion <-> Lion Hawk
  • Queen <-> Free Eagle
  • Rook General <-> Great General
  • Bishop General <-> Vice General
  • Chariot Soldier <-> Heavenly Tertarch
  • Dragon King <-> Soaring Eagle
  • Dragon Horse <-> Horned Falcon
  • Rook <-> Dragon King
  • Bishop <-> Dragon Horse
  • Side Soldier <-> Water Buffalo
  • Vertical Mover <-> Flying Ox
  • Lance <-> White Horse
  • Blind Tiger <-> Flying Stag
  • Gold General <-> Rook
  • Ferocious Leopard <-> Bishop
  • Silver General <-> Vertical Mover
  • Knight <-> Side Soldier
  • Kirin <-> Lion
  • Phoenix <-> Queen
  • Dog <-> Multi General
  • Pawn -> Tokin

Because promotion and demotion don't happen until the end of the turn, multi-capturing pieces that promote or demote have a chance for a double capture.

The King, Fire Demon, Vice General, and Tokin (promoted Pawn) do not promote or demote when making a capture.

Promoted pieces that demote when capturing have their names written in blue ink, and are called switchbacks (スイッチバック suitchibakku) because they alternate between their promoted and unpromoted states with every capture they make. Promoted pieces that do not demote when capturing have their names written in red ink to distinguish them from the switchbacks.

Check

When a player’s King is under immediate attack by at least one enemy piece, it is in check. A player who's King is in check is not required to remove the the check, but this is almost always the best option, since a player who has no King on the board loses the game. A check can be removed in one of three ways, depending on the situation:

  • Blocking the check by placing a piece in between the King and the attacking piece
  • Capturing the attacking piece
  • Moving to a safe square

The King need not move out of check, and can even move into check, though this is almost always a blunder. If it is not possible for a player to get out of check, that piece is checkmated and the game is effectively over.

A player is not allowed to give perpetual check.

Illegal Move

A player who makes an illegal move loses immediately. Illegal moves include:

  • Making more than one move per turn
  • Giving check four consecutive times
  • Skipping a turn four consecutive times
  • Moving a piece contrary to how its movements are defined

This rule may be relaxed in casual games, where a player can take back the illegal move and make a legal move.

End of the game

A player who captures the opponent's last remaining royal piece (a King or Prince) wins the game.

Checkmate and Stalemate

If a player’s last remaining royal piece is placed in check and there is no legal move that will resolve the check, the checking move is also checkmate, and effectively wins the game.

If a player’s last remaining royal piece is not in check but that player has no legal moves, the game is a stalemate. Stalemate, like checkmate, leads to a win for the stalemating player.

Resignation

At any point in the game, a player may resign and their opponent wins the game.

Draw

There are only two ways for a draw to occur - 千日手 sennichite (repetition) and impasse.

Repetition Draw 千日手 sennichite - If the same game position occurs four times with the same player to move, then the game ends in a draw, as long as the positions are not due to perpetual check or skipping a turn four consecutive times.

Impasse – If neither player can hope to force checkmate or stalemate on the other player’s last remaining royal piece or gain any further material through a series of legal moves, the players may agree to a draw.



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By Adam DeWitt.
Web page created: 2019-03-09. Web page last updated: 2019-03-09