How to Win at Gomoku (Five in a Row): Threes, Fours, and the Four-Three

Gomoku (five in a row, free style) looks simple — first to make five wins — but if you just place stones casually, your opponent builds a four and wins in a flash. Winning is about forcing the opponent to respond with threes and fours while you build your own winning shape.

Threes and fours — the units of attack

Attacks are built from "threes" and "fours." A three becomes a four next move if ignored. A four becomes five — the win — next move, so the opponent must block it. You use fours to force the opponent's reply, and in the meantime extend your own shape. Forcing moves keep the initiative on your side.

Open four and four-three — the winning shapes

A four with both ends open (an "open four") cannot be stopped in one move: block one end and your opponent still makes five at the other. So the moment you make an open four, you have won. Stronger still is the four-three — a single move that makes a four AND a live (open) three at the same time. The opponent must block the four, which leaves the three to become an open four next move. Almost every gomoku win ends in an open four or a four-three.

Defense — don't miss the opponent's threats

Defense matters as much as attack. You of course block the opponent's fours, but the key is not to ignore their live threes — an unanswered live three becomes an open four, which can no longer be stopped. Before pushing your own attack, always check whether the opponent could make a four-three or an open four.

How Renju differs from free-style gomoku

Competitive Renju restricts Black (the first player): a double-three, a double-four, and an overline of six or more stones are all illegal for Black, which curbs the first-player advantage. Free-style gomoku has no forbidden moves, and an overline (six or more) generally counts as a win. Get the feel for threes, fours, and the four-three in free play first; if you want a stricter, more balanced game, move on to Renju (and Renju VCF puzzles).

How to practice

The reading skill of forcing with fours carries straight over. TsumeDojo's Renju VCF (continuous-four) problems drill exactly that — once a forcing four-chase is easy to see, the paths to an open four or a four-three start to jump out in your own games too.