Guide · 15 min read
The Complete Gomoku Guide
From your very first game to a hard-level AI opponent, this is the full path to understanding the rules, building strong shapes and winning more often.
What is gomoku?
Gomoku, also called five in a row, is a board game for two players who take turns placing stones on a grid. The first player to line up five stones in an unbroken row wins. The rules take a minute to learn, yet the strategic depth comes from building several threats at once and forcing your opponent to answer only one of them. That gap between simple rules and deep play is what keeps people coming back.
The rules of play
Black moves first, and the players then alternate placing one stone per turn. You win by connecting five stones in a straight line — horizontally, vertically or diagonally. Depending on the version, the board may be a fixed 15×15 grid or a larger, open-ended board. Stones stay where they are placed: nothing is captured and nothing moves again after a turn. Because every stone remains on the board, each move permanently changes which lines are still available to both players.
Full guide: Gomoku rules →
Three pillars of strategy
- Attack: build open threes, open fours and double threats.
- Defence: block the correct open end, and never block too late.
- Opening: take the centre and keep your stones connected.
Strategy foundations: How to win at gomoku →
Effective openings
A good opening keeps your stones close to each other and close to the centre, so that each new stone creates options in several directions. Spread your stones too far apart and they stop supporting one another; pile them all into a single line and your opponent only has one direction to watch. The aim is a flexible cluster that can grow into an attack on either side of the board.
Details: Top 5 gomoku openings →
Defence and counterattack
Good defence means stopping the biggest threat first, then using that same blocking stone to start your own attack. When your opponent has four in a row, there is usually only one open end left, so the answer is forced. When they have an open three, block the end that gives them the more dangerous continuation. A block placed far away from your own stones may stop one line but leaves you with nothing to build on.
Defensive skills: Blocking and turning the game around →
Beating a hard-level AI
The AI blocks an immediate winning move and scores the patterns around stones already on the board, but it can only answer one threat per turn. That is the opening you need: create two open threes in different directions, or an open three and a four at the same time. Whichever one the AI blocks, the other should still be able to become five in a row. Forcing the computer to defend also tells you where it thinks the danger is.
Playing the computer: How to beat the gomoku AI →
International rules and variants
Gomoku is the free-style game most people play. Renju adds forbidden moves for Black, which removes some of the first player's easiest wins. Swap2 is an opening protocol designed to balance the advantage of moving first. Caro in Vietnam has many local variations, but nearly all of them still revolve around connecting five stones. Learning the differences helps you follow international play without being surprised by a rule you have never seen.
Gomoku and Renju rules: International rules →
Opening protocol: Swap2 rules →
Telling the games apart: Caro, gomoku and tic-tac-toe →
History and tournaments
Gomoku has old folk roots and eventually grew into competitive renju. The exact origins are told in different ways, but the game's simple appeal travelled across cultures long before it had a standard name. Today international renju and gomoku events are the best place to see how experienced players build shapes, choose between attack and defence, and convert a small advantage into a win. Following those games also shows why the same five-in-a-row idea can support both a casual family game and a serious competitive discipline.
Origins: History of gomoku →
International scene: Gomoku tournaments →
A 7-day learning plan
- Day 1: read the rules and play three games.
- Day 2: practise spotting open threes and open fours.
- Day 3: drill one centre opening.
- Day 4: practise blocking and counterattacking.
- Day 5: play the hard AI and use undo to learn from mistakes.
- Day 6: read the Gomoku, Renju and Swap2 rules.
- Day 7: play a friend and review the game afterwards.
Frequently asked questions
- Is caro the same as gomoku? They are essentially the same five-in-a-row game; the names and local rules can differ.
- Does moving first always win? Moving first is an advantage, but it does not guarantee a win if you make a tactical mistake.
- How big is a gomoku board? A traditional board is usually 15×15; Caro Classic uses an expanded board.
- How do I beat the AI? Create two threats at the same time and force the AI to defend only one side.