Game rules

Game Components

Ōgi pits two players against each other, seated face to face around an 8×8 board — 64 squares. In the tradition of Japanese board games, the players are called 先手(Sente), the player who moves first, and 後手(Gote), the player who moves second.

In the West, Sente and Gote are often referred to as Black and White, with Black making the first move.

Each player starts the game with 18 pieces. These pieces are flat, shaped like an irregular pentagon, and resemble an arrowhead. They come in several slightly different sizes. Apart from the King (see below), the pieces of both players are identical in appearance: only the pointed tip, oriented toward the opponent's camp, indicates ownership. The pieces range from the most important (the largest) to the least important (the smallest) as follows:

• 1 King
• 1 Gold General
• 1 Rook
• 1 Bishop
• 2 Silver Generals
• 2 Knights
• 2 Lances
• 8 Fu

Each piece bears its name in kanji, drawn in black ink. Every piece except the King has a promoted form, whose character is written on its reverse side. When a piece is flipped to that side during the game, it means it has been promoted and now has different movement abilities.

Example with the Fu:

Unpromoted side (front)

Promoted side (back)

The King can be represented by two characters, 王 and 玉: they are nevertheless the same piece (same rules and same movements); only the representation differs. The 玉 piece is called the Jeweled General: a purely cosmetic variant of the King (K^), used only when Ōgi faces Ōgi. By convention, both historical and honorific, it is assigned to the player with the lower rating (measured, for example, in Elo), or to Sente if ratings are equal, so that only one King (王) stands on the board: the lower-ranked player thus expresses their respect toward the higher-ranked player. When Ōgi faces chess or xiongqi on the same board, the Jeweled General is never used. In notation, the Jeweled General may optionally be written K^' (k^' for Gote); a canonical record of the position writes both Kings K^.

Below is the list of pieces and, for each one, its name, the Japanese character used on the piece, as well as its notation abbreviation. These abbreviations follow the EPIN convention: uppercase letters denote Sente's pieces, lowercase letters Gote's (for example K^ for Sente's King, k^ for Gote's), and the + prefix marks a promoted piece (+F for the Tokin). The images show the pieces as oriented for Sente; Gote's are identical, rotated 180°.

Pieces

Name	Unpromoted			Promoted
	Abbr.	Kanji	Image	Abbr.	Kanji	Image
King	K^	王		—	—	—
Jeweled General	K^'	玉		—	—	—
Gold General	G	金		+G	姫
Rook	R	飛		+R	龍
Bishop	B	角		+B	馬
Silver General	S	銀		+S	全
Knight	N	桂		+N	圭
Lance	L	香		+L	杏
Fu	F	歩		+F	と

Rules of the Game

Objective

The goal of the game is to checkmate the opposing King: to place it under an attack from which it can no longer escape. As in shōgi and Western chess, putting or leaving one's own King in check is illegal; the King is therefore never actually captured — checkmate decides the game. A game can also end in other ways (resignation, draw): see End of the game.

Setup

At the start of the game, the two players place their pieces on the board, each oriented toward the opponent's camp. The arrangement is that of shōgi, brought down to eight files:

Initial position of an Ōgi game.

Unless otherwise indicated, diagrams are shown from Sente's point of view, with Sente at the bottom. Files are labelled a to h from left to right, and ranks 1 to 8 from bottom to top (from Sente's point of view). In movement diagrams, highlighted squares indicate the possible destinations of the pictured piece (a move, or a capture if an opposing piece stands there).

First player's camp (Sente)

Rank 1: Lance, Knight, Silver General, Gold General, King (shown as the Jeweled General), Silver General, Knight, Lance. Rank 2: the Bishop on b2 and the Rook on g2 — the Bishop on the player's left, the Rook on their right, as in shōgi. Rank 3: one Fu on each square.

Second player's camp (Gote)

Rank 8: Lance, Knight, Silver General, Gold General, King, Silver General, Knight, Lance. Rank 7: the Rook on b7 and the Bishop on g7 — again on their player's left and right. Rank 6: one Fu on each square. Ranks 4 and 5 are empty. The Gold General stands on the d-file and the King on the e-file for both players, as the Queen and the King do in chess: the arrangement is therefore not symmetric under a 180° rotation. In FEEN notation, the initial position reads lnsgk^snl/1r4b1/ffffffff/8/8/FFFFFFFF/1B4R1/LNSGK^SNL / J/j.

Piece Movements

On each turn, a player performs exactly one of the following two actions: either move a piece already on the board (which may result in a capture and/or a promotion), or drop a previously captured piece. Players alternate turns; Sente moves first. No piece jumps over another, except the Knight. There is no castling.

King

Movements: King

The King (玉 / 王) moves a single square per turn, in any direction (forward, backward, left, right or diagonally), and captures the same way. It cannot be promoted.

Gold General

Movements: Gold General

The Gold General (金) moves one square to one of six destinations: one square orthogonally in the four directions, or one square diagonally forward (two diagonals). It cannot move diagonally backward, and captures the same way it moves. It is the shōgi Gold General; unlike in shōgi, however, it promotes, to the Free Gold.

Rook

Movements: Rook

The Rook (飛) moves any number of squares in a straight line, along a rank or a file, never jumping over pieces. It captures by ending its move on the opposing piece. It promotes to the Dragon.

Bishop

Movements: Bishop

The Bishop (角) moves diagonally over as many squares as desired, without jumping over pieces, and captures by stopping on the opposing piece. It promotes to the Horse.

Silver General

Movements: Silver General

The Silver General (銀) moves one square to one of five destinations: one square straight ahead, or one square diagonally in any of the four diagonals. It cannot move straight backward or sideways. It captures the same way it moves. It promotes to the Gold General's movement.

Knight

Movements: Knight

The Knight (桂) is the shōgi Knight: it leaps two squares forward and one square sideways, to the left or to the right — two destinations at most — and never backward or sideways. It jumps over any intervening pieces and captures by landing on an opposing piece. It therefore does not move like the Knight in Western chess. It promotes to the Gold General's movement.

Lance

Movements: Lance

The Lance (香) slides any number of squares straight ahead along its file, without jumping over pieces, and never backward or sideways. It captures by ending its move on the opposing piece. It promotes to the Gold General's movement.

Fu

Movements: Fu

The Fu (歩) moves a single square straight ahead, on the same file, and can never move backward. It captures the same way: by advancing one square straight ahead onto an opposing piece (there is no diagonal capture as in Western chess). There is no double step. It promotes to the Tokin.

Tokin, promoted Lance, Knight and Silver General

Movements: Tokin

The Tokin (と, the promoted Fu), the promoted Lance (杏), the promoted Knight (圭) and the promoted Silver General (全) all move alike, one square to one of six destinations: one square orthogonally in the four directions, or one square diagonally forward (two diagonals). They cannot move diagonally backward: it is the movement of the Gold General. None of them can be promoted further.

Free Gold (promoted Gold General)

Movements: Free Gold

The Free Gold (姫; 奔金 in shōgi) is the promoted Gold General: it slides any number of squares in six directions, in a straight line along its rank or its file, in the four orthogonal directions, like the Rook, and diagonally forward, along the two forward diagonals. It never moves diagonally backward. It does not jump over pieces and captures by ending its move on the opposing piece. It is the movement of the Gold General, extended to the full length of the board. It cannot be promoted further.

Horse (promoted Bishop)

Movements: Horse

The Horse (馬) is the promoted Bishop: it keeps the Bishop's diagonal slide and adds one square in the four orthogonal directions. It cannot be promoted further.

Dragon (promoted Rook)

Movements: Dragon

The Dragon (龍) is the promoted Rook: it keeps the Rook's orthogonal slide and adds one square in the four diagonal directions. It cannot be promoted further.

Promotion

A player's promotion zone consists of the last three ranks of the board as seen from their side: ranks 6, 7 and 8 for Sente, ranks 3, 2 and 1 for Gote — the opponent's camp, where the opponent set up their pieces.

The rule is that of shōgi. A move that brings a piece into the zone, moves it within the zone or takes it out of the zone may promote it: the player chooses, and the piece is flipped on arrival. A piece that does not promote on such a move may do so on a later move meeting the same condition. Promotion is mandatory when the piece, left unpromoted, would have no move left: a Fu or a Lance reaching the last rank, a Knight reaching either of the last two ranks.

Sente's promotion zone: the last three ranks (in yellow)

The King does not promote; the Gold General is never forced to, since it always has a move. A promoted piece does not promote again. A drop never triggers promotion: the piece is placed as it is in hand, unpromoted, even inside the zone.

Captures and pieces in hand

When a piece is captured, it does not leave the game for good: it is removed from the board and placed in the reserve of the player who captured it. It is then said to be held in hand. In Japanese, these pieces are called 持ち駒(mochigoma) or 手駒(tegoma).

The transformation of the captured piece follows two rules, applied in order:

1. Demotion. The piece reverts to its unpromoted form: a captured Tokin becomes a Fu again, a Dragon a Rook, a Horse a Bishop, a Free Gold a Gold General, a promoted Lance, Knight or Silver General the original piece. Unpromoted pieces are unchanged by this step.
2. Change of camp. The piece joins its captor's camp (its case is flipped: uppercase ↔ lowercase).

Every captured piece thus changes camp: it ends up in its captor's camp and becomes, in principle, droppable again (subject to the restrictions below). It is never possible to keep a promoted piece in hand: it always becomes the original piece again. The King, which is never captured, is never in hand.

Instead of moving a piece already on the board, a player may, on their turn, drop a piece they hold in hand: they place it on an empty square, and the piece then joins their active pieces. Each drop counts as a complete turn. A drop cannot capture (the destination square must be empty) nor promote the piece, even inside the promotion zone.

Restrictions on drops

Thanks to the systematic change of camp, every piece in hand belongs to its holder's camp and can, in principle, be dropped. A drop is illegal if it violates any of the following restrictions:

• No drop without a future move. A piece cannot be dropped where it could never move again: a Fu or a Lance on its own last rank (rank 8 for Sente, rank 1 for Gote), a Knight on either of its last two ranks.
• Nifu (二歩(nifu)). A Fu cannot be dropped on a file where the player already has an unpromoted Fu on the board. A Tokin on the file does not trigger nifu: only unpromoted Fu count.
• Uchifuzume (打ち歩詰め(uchifuzume)). A Fu cannot be dropped on a square if doing so would deliver checkmate. Simply giving check with a Fu drop is allowed; only mate is forbidden, and mate by the drop of any other piece is allowed.

The other pieces (Rook, Bishop, Silver General, Gold General) can move from any square of an 8×8 board: no square restriction applies to them.

Check

A King is in check (王手(ōte)) when it is attacked by an opposing piece, meaning it could be captured on the next move. A player whose King is in check must play a move that ends the check: moving the King to a safe square, capturing the checking piece, or interposing a piece on the line of attack — moved or dropped.

A move that leaves one's own King in check is illegal — whether it creates a new check or fails to parry an existing one. Check does not need to be announced. Since self-check is forbidden, the King is never actually captured: a player in check with no legal move to escape it is checkmated and loses the game.

End of the game

The game ends in one of the following cases:

• Checkmate: the player to move is in check and has no legal move to escape it. They lose.
• Stalemate: the player to move has no legal move (drops included) and is not in check. The game is a draw. (This is a deliberate departure from shōgi, where stalemate loses; Ōgi aligns here with chess.)
• No possible move: the player to move cannot make any move or drop at all, not even one that would leave their own King in check — every piece is blocked and the hand is empty. The game is a draw, whether or not the King is in check; this takes precedence over checkmate.
• Threefold repetition: if the same position occurs three times during the game (not necessarily in a row), the game is a draw, as in chess. A “draw by perpetual check” therefore remains available to the defender.
• Dead position: if a position arises in which neither player can checkmate by any series of legal moves, the game is immediately drawn. In Ōgi, captures never remove material from play — a captured piece goes to the capturer's hand and remains droppable — so no dead position can arise from material alone, and none is ever declared: a fully blocked position ends by repetition or by the 50-move rule.
• Draw by agreement: the players may agree at any time that the game is a draw.
• Resignation: a player concedes the game; the opponent wins.
• 50-move rule: if 50 moves by each player (that is, 100 half-moves, drops included) are played without any capture and without any move of an unpromoted Fu on the board, the game is automatically a draw. A drop — even a Fu drop — counts as a half-move but resets nothing: it neither captures nor moves a Fu already on the board.

A game therefore has exactly one of three results: 1–0 (Sente wins), ½–½ (draw) or 0–1 (Gote wins). Checkmate and resignation are decisive; stalemate, no possible move, threefold repetition, dead position, draw by agreement and the 50-move rule are draws.

Illegal moves

On Sashité, an illegal move does not end the game: it is simply refused. The player keeps the turn and must submit another move. The following constitute illegal moves:

• Playing anything other than a move or a drop.
• Moving a piece to a square not allowed by its movement rules.
• For sliding pieces (Rook, Bishop, Lance, Free Gold, and the slides of the Dragon and the Horse), passing through an occupied square. (The Knight jumps: it is exempt.)
• Moving a piece onto a square occupied by a friendly piece.
• Leaving one's own King in check (any move that creates or fails to resolve a check on one's King).
• Dropping on a non-empty square.
• Dropping a piece whose camp does not match the player's.
• Dropping a Fu or a Lance on the last rank, or a Knight on either of the last two ranks.
• Dropping a Fu on a file where one already has an unpromoted Fu (nifu).
• Dropping a Fu that would deliver checkmate (uchifuzume).
• Promoting on a move that neither starts nor ends in one's promotion zone.
• Promoting the King.
• Promoting during a drop.
• Promoting an already promoted piece.
• Failing to promote when it is mandatory (a Fu or a Lance reaching the last rank, a Knight reaching either of the last two).

Cultural narrative and urban legend

Ōgi preserves the fundamental principles of Shōgi, but distinguishes itself through a contemporary narrative rather than documented historical origins. The game was formalized and named by the French author Cyril Veltin, who recounts having discovered it while observing, one summer evening, a strange game being played in a park in Ōsaka.

At the heart of this cultural narrative lies an urban legend involving a yōkai named Komayō, who is said to sometimes invite players to a game, under the light of the full moon.

Some players claim to have seen her. Others do not believe.