Gomoku rules

🎯 Game Objective

Objective: Be the first to line up five of your stones in an unbroken row — horizontally, vertically, or diagonally.

Board: stones are placed on the intersections of a 15×15 grid. Black plays first.

📋 Basic Rules

Placing stones

Players alternate turns. On your turn you place one stone of your color on any empty intersection. Stones are never moved or removed once placed.

Black moves first

Black always makes the first move. Because moving first is an advantage, competition play uses an opening rule (see below) to keep the game fair.

Winning

The first player to align exactly five or more of their own stones in a row (in any of the eight directions) wins immediately. This "freestyle" variant counts a row of six or more as a win too.

Draw

If the whole board fills up without any five-in-a-row, the game is a draw.

⚖️ Opening Rules (fairness)

Playing first is a real edge in Gomoku: with no restriction, a strong Black can force a win. The game offers four opening rules, selectable before starting a game.

Free

No restriction at all. The most casual setting — Black keeps the natural first-move advantage.

                Pro (restricted opening)
                Black's first stone must be played at the center of the board.
Black's second stone must be placed at least three intersections away from the center (outside the central 5×5 square).
White is never restricted. These two constraints blunt Black's opening edge.

            

                Swap 1 — choose your color
                One player (the opener) freely places the first three stones: two black and one white, forming an opening of their choice.
The opponent then chooses which color to play for the rest of the game.
Knowing the opponent will take the better side, the opener is pushed to build a balanced position.

            

                Swap 2 — tournament standard
                The opener places three stones (two black, one white).
The opponent then has three options:
                        take Black,
take White,
or add two more stones (one white, one black) and hand the color choice back to the opener.

                    
This double option is the strongest balancer known: the opener must propose a position as even as possible, or risk being handed the losing side.

            

After the opening is settled, White is always the side to move first in the ongoing game.

💡 Strategy Tips

                🎯 For beginners
                Build and block at once: a stone that extends your line while limiting the opponent's is worth two.
Watch open threes: an unblocked row of three becomes an unstoppable open four if ignored — block it in time.
Create double threats: a move that makes two separate winning threats cannot be blocked by a single reply.
Beware gaps: patterns like ✕✕_✕✕ are a win-in-one — count the empty point in the middle, not just contiguous stones.

            

                ⚠️ Pitfalls
                Don't chase your own attack while missing the opponent's four.
Don't forget the two diagonals — most missed wins are diagonal.
A "four" that is blocked on both ends is harmless; an open four is not.

            