Variants · 5 min

What Is the Swap2 Rule in Gomoku — and Why Is It Fair?

Swap2 is an opening protocol that stops the second player from being at too great a disadvantage. Instead of arguing over who moves first, both players use the first three moves to choose a colour and a position.

The problem: the first-move advantage

In free-style gomoku, Black has a clear advantage because Black chooses the first move and sets the direction of the game. When two players are evenly matched, the player who moves first often holds the initiative from the opening. Tournaments need a way to share that advantage fairly, rather than deciding the result before the first stone is even placed. Swap2 is one answer to that problem.

How does Swap2 work?

The first player places the first three stones: two Black and one White.
The second player chooses one of three options: take Black, take White, or place two more stones (one Black and one White).
If the second player adds stones, the first player then chooses a colour after seeing the position.
The game continues under the agreed renju or gomoku rules.

Why is Swap2 fair?

The second player sees the position before choosing a colour, so they are not forced into a bad position without a say. If the three-stone opening is too strong for Black, they can take White; if it is too weak for Black, they can take Black. The first player also gets a chance to balance the position by adding the extra stones. Neither side is guaranteed a comfortable game, but both sides get to make an informed choice.

Is Swap2 in Caro Classic?

Caro Classic does not currently have a Swap2 mode. The game uses free-style gomoku with no forbidden moves. Even so, understanding Swap2 helps you follow renju events and international gomoku tournaments, where the opening protocol is part of the format. It also makes the trade-offs in the opening easier to see when you watch strong players choose a side.

When should you use Swap2?

Swap2 is a good choice when two players want a fair game without giving handicap stones. It adds a short negotiation to the start, but that negotiation is the point: it turns the first-move advantage into a decision that both players share. For casual play, free-style gomoku remains the simpler option, because you can sit down and start without explaining a protocol first.