ogi

Ōgi (王棋) is a strategy board game derived from Shōgi (Japanese chess), which was invented by Cyril Veltin in 2023. The name Ōgi translates to king's (王) board game (棋).

Setup

At the beginning of the game, both players arrange their pieces on the board with each piece facing the opponent. This setup signals the readiness of the pieces to move forward into play.

Here is how the pieces are arranged at the start of the game:

Typically, diagrams showing the board are illustrated from the viewpoint of the Black player, who is positioned at the bottom side of the diagram.

Pieces

Each player starts the game with 18 pieces. These pieces are flat, wedge-shaped, and pentagonal, differing slightly in size. All pieces except for the kings are identical in appearance, regardless of which player they belong to. To show a piece's direction, its pointed end faces towards the opponent's side of the board, indicating who controls the piece. The pieces range from the most significant (the largest) to the least significant (the smallest) as follows:

• 1 King
• 1 Princess
• 1 Rook
• 1 Bishop
• 2 Silver Generals
• 2 Knights
• 2 Lances
• 8 Pawns

Below, you'll see a list of the pieces, their names in Japanese, and their corresponding English names. These abbreviations are commonly used in game notation and when referring to the pieces in conversation.

Pieces

	Not promoted				Promoted
Name	Abbr.		Image		Abbr.		Image
King	K	王
Princess	I	姫			+I	神
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
Pawn	P	歩			+P	と

The list below details the movement patterns of each piece.

King

A king ( 玉 / 王 ) moves one square in any direction, orthogonal or diagonal.

Princess

A princess ( 姫 ) moves as a bishop and as a knight, including the knight's ability to move forward, backward, or to the sides.

Promoted Princess

A promoted princess ( 神 ) moves as a princess and as a king.

Rook

A rook ( 飛 ) moves any number of squares in an orthogonal direction.

Promoted Rook

A promoted rook ( 龍 ) moves as a rook and as a king.

Bishop

A bishop ( 角 ) moves any number of squares in a diagonal direction.

Promoted Bishop

A promoted bishop ( 馬 ) moves as a bishop and as a king.

Silver General

A silver general ( 銀 ) moves one square diagonally, or one square straight forward, giving it five possible destinations.

Promoted Silver General

A promoted silver general ( 全 ) moves one square orthogonally, or one square diagonally forward, giving it six possible destinations. It cannot move diagonally backwards.

Knight

A knight ( 桂 ) jumps at an angle intermediate to orthogonal and diagonal, amounting to one square straight forward plus one square diagonally forward, in a single move. Thus the knight has two possible forward destinations. Unlike Western chess knights, Ōgi knights cannot move to the sides or in a backwards direction. The knight is the only piece that ignores intervening pieces on the way to its destination. It is not blocked from moving if the square in front of it is occupied, but neither can it capture a piece on that square.

Promoted Knight

A promoted knight ( 圭 ) moves the same way as a promoted silver general.

Lance

A lance ( 香 ) moves just like the rook except it cannot move backwards or to the sides.

Promoted Lance

A promoted lance ( 杏 ) moves the same way as a promoted silver general.

Pawn

歩 ) moves one square straight forward. It cannot retreat. Unlike Western chess pawns, Ōgi pawns capture the same as they move.

Promoted Pawn

A promoted pawn ( と ) moves the same way as a promoted silver general.

Rules

Differences from Traditional Shōgi

Ōgi exclusively differs from traditional Shōgi in the following key aspects, with all other aspects of gameplay remaining consistent:

Board Size

The game is played on an 8x8 grid, making a total of 64 squares, in contrast to Shōgi's 9x9 board.

Drop Rule

Ōgi allows for checkmate by dropping a pawn, a maneuver that is not permissible in traditional Shōgi.

Pieces

Changes in the composition of pieces for Ōgi are as follows:

• The Gold General piece is omitted.
• A new piece, named the Princess, is introduced. This piece combines the movement capabilities of a Bishop and a Knight, including the Knight's lateral movement—forward, backward, or to the sides, akin to the Knight in Western chess.

Promotion

In Ōgi, whenever a piece's promotion is optional in traditional Shōgi, such promotion becomes mandatory. This rule ensures that whenever a piece moves into, out of, or within the promotion zone under conditions that would allow for optional promotion in Shōgi, it must be promoted in Ōgi.

Gameplay Rules

The primary aim of the game is to checkmate your opponent's king. Achieving this results in winning the game.

Determining Who Plays Black

A method called 振り駒 ( furigoma ) or piece toss is used to decide who moves first. One player tosses five pawns. If the number of promoted pawns (と) facing up exceeds the number of unpromoted pawns (歩), then that player will play as White, meaning they will make the second move.

After the initial piece toss, the game begins. If multiple games are played in succession, players alternate the role of moving first in subsequent games. On each turn, a player can either move a piece already on the board (potentially promoting it, capturing an opposing piece, or both) or place a previously captured piece back on the board. These options are detailed below.

Promotion

The promotion zone for each player is the three furthest ranks on the board, initially occupied by the opponent's pieces. A piece entering, moving within, or exiting the promotion zone during a move (but not when dropped) must be promoted at the turn's end. Promotion is signified by flipping the piece to show the character of its promoted state.

A captured piece reverts to its unpromoted state. Except when captured, a piece's promotion is irreversible.

Drops

Players keep captured pieces in hand to potentially reintroduce them to the game. In Japanese, these are called 持ち駒 ( mochigoma ) or 手駒 ( tegoma ) . Instead of moving a piece on the board, a player can place a piece from their hand onto any empty square, with the unpromoted side up. This reintroduces the piece into play as one of that player's active pieces, and this action is known as a drop. Each drop is considered a complete move.

Dropping a piece does not allow for capturing an opponent's piece or immediate promotion if placed within the promotion zone. However, the dropped piece can capture or be promoted on future moves as usual.

Restrictions

There are specific rules that limit how certain pieces can be dropped:

• Piece with No Moves ( 行き所のない駒 ( ikidokorononaikoma ) ): Pawns, lances, and knights cannot be dropped on the last rank (8th), and knights also cannot be dropped on the penultimate rank (7th). This is because such positions would leave these pieces without any legal moves on their next turn, given their forward-only movement.
• Two Pawns ( 二歩 ( nifu ) ): A pawn cannot be dropped in a file (column) that already has an unpromoted pawn of the same player. This rule does not apply to promoted pawns.

Check

If a king could be captured on the opponent's next move, it is in a state known as check. When a king is in check, the player must make a move to protect the king. This can be done by moving the king to a safe square, capturing the piece that is threatening the king, or blocking the threat with another piece.

End of the Game

Most Ōgi games end with a checkmate, where one player captures the opponent's king and wins the game. In Ōgi, because pieces remain in play after being captured and can be returned to the board, there are usually enough pieces available to achieve checkmate.

However, games can also end through repetition, where the same series of moves is repeated (though this is rare), or by an illegal move, which is uncommon in professional games.

Notes

While Western chess venerates the mythological Thracian dryad Caïssa as its deity, the origins of Ogi are shrouded in whispers of an urban legend. It is rumored that the game is linked to a yokai named Komayō, adding layers of mystery and folklore. However, whether this tale is a mere figment of imagination or holds a deeper truth remains a tantalizing uncertainty, casting a veil of enchantment and intrigue over Ogi, reminiscent of the rich tapestry of Japanese mythology.

Last revised by Cyril Veltin.