Gomoku Strategy Basics: Forks, Open Fours, and Winning Tactics
You know the rules. You can play. But you keep losing to people who seem to see three moves ahead. What do they know that you don’t?
Here’s the thing: nobody gets good at Gomoku by memorizing openings. Unlike Chess, where you can study theory for years before you’re competitive, Gomoku rewards a small set of tactical ideas that you can pick up in an afternoon.
The One Concept That Changes Everything: Forks
A fork is a move that creates two threats at once. Your opponent can only answer one — and you win with the other.
The simplest fork: place a stone that simultaneously creates an open three in two different directions. Your opponent blocks one. You complete the other. Game over.
Every strong Gomoku player thinks in forks. When you make a move, ask yourself: “Am I creating one threat, or two?”
Attack vs. Defense
When to Attack
You should attack when you have initiative — meaning your threats are forcing your opponent to respond. If you’re making moves and your opponent is just blocking, you’re in control.
Signs you have initiative:
- You have an open three they must block
- You have multiple groups developing on different parts of the board
- Your opponent’s stones are scattered and defensive
When to Defend
Defense isn’t just blocking. A good defensive move blocks a threat while also building your own position. Look for blocks that also connect your stones or create new possibilities.
If you only react, you will lose. Every defensive move should serve double duty when possible.
The Dangerous Patterns You Must Recognize
Open Four
Four stones in a row, with empty spaces on both ends. If you create an open four, you’ve won — your opponent can only block one side, and you’ll complete the five on your next turn.
Open Three
Three stones in a row, with empty spaces on both ends. If your opponent has an open three, they can place a fourth stone on either end — and you can only block one side. This is a one-move-away loss. If you don’t block immediately, you lose on their next turn.
Stop open threes before they happen. Block them at two stones if you can.
Double Three (3-3)
A single move that creates two open threes. In standard Gomoku, this is legal and almost always wins the game. In competitive Renju rules, this is forbidden for black — but for casual play, it’s one of your strongest weapons.
Double Four (4-4)
A single move creating two open fours. Devastating. Your opponent cannot block both.
Practice: Find the Fork
Can you spot the winning move? Each board shows black’s stones. Click where you think black should place the next stone to create a fork.
Double Three Fork
Double Four Fork
Opening Strategy
The center of the board is the most valuable territory on move one. A stone in the center can expand in all directions. A stone in the corner has far fewer options.
Most strong players open near the center and build outward. Control the middle, and you control the game.
One Practical Drill
Play against our AI on Easy. Before every move — yours and the AI’s — ask yourself:
- What is the biggest threat on the board right now?
- If I ignore it and make my own move, what happens?
Do this consciously for five games. You’ll start seeing the board differently.
If the double-three and double-four tactics have you curious about competitive play, Renju Rules Explained covers the tournament version of the game — same board, stricter rules, and a much fairer fight.