Learn Gomoku: Tutorial

Players alternate turns. Black places first, then White, then Black again, and so on.

Here Black has opened at the center (H8), White responded nearby at G7, and Black played I9. Once placed, stones are permanent — they cannot be moved or removed.

A player wins by placing five stones in an unbroken horizontal, vertical, or diagonal line.

In this example, Black has completed a horizontal line of five stones across row 8 (columns D through H). The game ends immediately when the fifth stone is placed.

Winning lines can run in four directions: horizontal, vertical, and both diagonals.

This example shows White winning with a diagonal line running from the upper-left to the lower-right (D11 through H7). Watch for threats in all four directions — a line can form anywhere on the 15x15 grid.

When your opponent builds a line of three or four stones, you must block one end to prevent them from reaching five.

Here Black has four stones in a vertical line (H11 down to H8). White must immediately play at H12 or H7 to block — otherwise Black completes five on the next move. Failing to block a "four" is almost always a losing mistake.

An open four is a line of four stones with both ends empty — it guarantees a win because the opponent cannot block both sides at once.

An open three is a line of three stones with both ends empty. It threatens to become an open four on the next move. Building two open threes simultaneously (a "double three") is a powerful tactic — the opponent can only block one, and the other becomes an unstoppable open four.

The key to Gomoku strategy is creating these overlapping threats while preventing your opponent from doing the same.

The game ends the moment a player completes five in a row. Here Black wins with a diagonal line from E11 to I7.

If the entire 15x15 board fills up without either player forming five in a row (extremely rare), the game is a draw. In practice, games are decided well before the board is full.

Remember: control the center, build open threes, watch for double threats, and always check all four directions!

The Swap2 opening is a balancing protocol used in tournament Gomoku. It prevents a first-player advantage by giving both players a say in the opening position.

Phase 1: Player 1 places 3 stones — 2 Black and 1 White — anywhere on the board. These are the opening stones that set the stage for the game.

Phase 2: Player 2 looks at the 3 stones and chooses one of three options:

- Play as Black (accepting the position)

- Play as White (accepting the position but switching sides)

- Place 2 more stones (entering Phase 3)

In this example, Player 1 has placed 2 Black stones and 1 White stone. It is now Player 2's turn to choose.

If Player 2 chose "place 2 more", the game enters Phase 3. Player 2 places 2 additional stones (1 Black and 1 White) on the board, bringing the total to 5 stones (3 Black, 2 White).

After Phase 3, the protocol moves to Phase 4: Player 1 picks which color they want to play. Since Player 2 placed the extra stones, they had influence over the position — but Player 1 gets the final say on sides.

This back-and-forth ensures a fair and balanced opening. Neither player can guarantee themselves a dominant position.

In this example, Player 2 has placed 2 more stones after choosing "place 2 more". Player 1 must now decide: play as Black or White?