SETO is a strategy board game where victory is achieved by creating predefined scoring patterns rather than capturing your opponent's pieces. Every move requires planning, positioning, and timing. Players must build their own patterns while disrupting their opponent's strategy, making each game unique and highly tactical.

The first player to score 7 points declares "SETO!" and wins the game.

Each player receives eight playing pieces consisting of:

• Four square pieces
• Four circular pieces

Each piece displays one of four movement symbols:

• Triangle (Delta)
• Circle (Omega)
• Square (Tetra)
• X (Chi)

The symbol determines how the piece moves, while the physical shape (circle or square) determines how it is used for scoring patterns.

To determine colors, one player secretly holds one white piece in one hand and one red piece in the other. The opposing player chooses one hand. The selected color becomes that player's color for the remainder of the game.

The player controlling the white pieces moves first.

Both players arrange their eight pieces on the board in the prescribed starting zigzag formation.

Before normal play begins, each player selects one of their eight pieces to become their Key.

The white player begins by moving the selected Key outside the board, placing it immediately beyond either end of its current row or column. The piece may be positioned horizontally or vertically outside the board.

The red player then performs the same opening procedure.

Once a Key has been moved outside the board, it becomes temporarily inactive. On the player's following turn, they must first make a normal move with another piece still inside the board before the Key may become eligible to return under the Return rules.

Players alternate turns, moving one piece at a time according to the symbol displayed on that piece.

• Triangle: One square in any direction. May jump over one friendly piece.
• Circle: One square in any direction. Cannot jump.
• Square: One square horizontally or vertically. May jump over one friendly piece.
• X: One square horizontally or vertically. Cannot jump.

During normal play, pieces may never jump over an opponent's piece.

The objective is to form one of 20 predefined scoring patterns.

• 18 patterns require four pieces of the same shape (all circles or all squares). Each is worth 1 point.
• 2 special patterns require all eight of a player's pieces and are worth 2 points.

Only pieces completely inside the 4×4 board may be used to score.

The first player to accumulate 7 points immediately declares "SETO!" and wins the game.

When a player completes a scoring pattern, the last piece moved into position becomes the Ace.

All remaining pieces that form the pattern become the Relay.

The Ace remains protected during the Break and cannot be moved.

Immediately after a player scores, the opponent must perform a Break before taking their normal turn.

During the Break, the opponent selects one Relay piece from the completed pattern and relocates it to any vacant square on the board. This relocation ignores the piece's normal movement rules.

Once the Break is completed, the same player immediately takes a normal turn.

The Break prevents completed scoring patterns from remaining intact and adds an important defensive element to the game.

A Key positioned outside the board may return in two different ways.

If the square immediately inside the board beside the Key becomes vacant, the owner may return the Key directly into that square on their turn.

If a player forms what would otherwise be a scoring pattern using three pieces inside the board and one Key outside the board, no point is awarded.

Instead, the opponent immediately places the outside Key onto any vacant square on the board before taking their normal turn.

A Switch allows a player to exchange the positions of two of their own pieces that bear the same movement symbol, with one being a circle and the other a square.

A Switch is allowed only when:

• A Switch may be performed only between two pieces belonging to the same player that bear the same movement symbol.
• The two pieces must be adjacent horizontally or vertically. Diagonal Switches are not permitted.
• The Switch must immediately form a valid scoring pattern. Otherwise, it cannot be performed.
• All pieces participating in the Switch and the resulting scoring pattern must be positioned inside the Main Play Area (4×4 board).
• Each movement symbol (Triangle, Circle, Square, and X) may perform only one Switch per player during a game.

Each player is granted one Vault per game.

A Vault may only be performed by a Triangle or Square piece.

When using a Vault, the selected piece may jump over one opposing piece, something that is normally not allowed.

• Triangle pieces may Vault horizontally, vertically, or diagonally.
• Square pieces may Vault horizontally or vertically.

A Vault may be used to score, defend, escape a difficult position, or create new strategic opportunities.

Once used, it cannot be used again for the remainder of the game.

Continue building patterns, defending against your opponent, and making strategic use of the Key, Break, Return, Switch, and Vault mechanics.

The first player to reach 7 points proudly declares:

and wins the game.