If you have searched for "five in a row" online, you have probably seen two names: Gomoku and Renju. They look almost identical, but they are different games with different rules, opening theory, and competitive scenes.
Quick Answer
Gomoku is the simple, free-form version of five in a row: first to five wins, no restrictions. Renju is the professional variant that adds restrictions on Black's first moves and certain shapes to balance the game's first-player advantage.
Rules Comparison
Common Rules
- Played on a 15×15 grid of intersections.
- Two players: Black and White.
- Players alternate placing one stone per turn on an empty intersection.
- The first to align exactly five stones in a row — horizontally, vertically, or diagonally — wins.
Where They Differ
| Aspect | Gomoku | Renju |
|---|---|---|
| First-move advantage | Black has a strong theoretical advantage | Balanced by restrictions on Black |
| Opening restrictions | None — play anywhere | Black's first three moves are restricted to approved openings |
| Overlines (6+ in a row) | Often count as a win in casual rules; sometimes excluded in tournaments | Do not count as a win for Black; Black loses if forced to make six or more |
| Forbidden moves for Black | None | Double three, double four, and overline are forbidden |
| Common board size | 15×15 (also 19×19 casually) | 15×15 |
| Professional scene | Casual + freestyle tournaments | Organized international sport with world championships |
Why Renju Exists
Strong Japanese players noticed in the late 19th century that Black had a clear winning advantage in unrestricted Gomoku — a fact later confirmed by computer analysis in 1994. To make the game competitive, they developed Renju with specific rule changes:
- Opening restrictions limit Black's first three moves to a set of balanced positions, preventing the most aggressive opening patterns.
- Forbidden moves for Black ban double three, double four, and overline. White has no such restrictions.
- Asymmetric rules mean the same move can be legal for White and illegal for Black, which makes Renju strategically richer than standard Gomoku.
Which Should You Play?
Play Gomoku if you are…
- A beginner who wants simple rules and quick games.
- A casual player with friends or family.
- An AI or programming enthusiast — Gomoku is a standard testbed for game-tree algorithms.
- Looking for a game with universal rules that are the same everywhere.
Play Renju if you are…
- An intermediate-to-advanced player looking for deeper strategy.
- Interested in competitive play — Renju has an organized international federation (the International Renju Federation) and world championships.
- Willing to learn the opening restrictions and forbidden-move rules.
Other Notable Variants
Beyond Gomoku and Renju, the five-in-a-row family includes several regional and modern variants:
- Freestyle Gomoku — competitive Gomoku with no restrictions. Common format for online tournaments.
- Omok (오목) — the Korean name for the game. Casual Korean rules usually do not count overlines as a win.
- Caro (Cờ ca-rô) — the Vietnamese variant, often played on graph paper. Some local rules restrict the first move to non-center points.
- Pente — a Western commercial variant where pairs of stones are captured by flanking them, blending Gomoku and Go-like capture ideas.
- Connect6 — a modern variant in which Black plays one stone on the first move and each player plays two stones per turn afterward, designed to remove the first-player advantage.
Try Them Both
You can play standard Gomoku right now on MiniGameHub. To try Renju, look for an online Renju server or a dedicated Renju app. The rules take an afternoon to learn; mastery takes much longer.
Whichever variant you choose, the core appeal of five in a row stays the same: a simple idea that turns every game into a small contest of planning and foresight.