⚠️ Renju Rules — Black's Forbidden Moves
White has no forbidden moves. Both players must enforce these rules themselves during play. Full Renju rules explained →
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How to Play Renju Online
Renju is the professional tournament variant of Gomoku. Both games are played on the same 15×15 board with the same goal — get exactly five stones in a row — but Renju adds forbidden moves for Black to balance the first-player advantage.
Renju vs Gomoku: Key Difference
In freestyle Gomoku, Black (the first player) has a proven theoretical advantage. Renju corrects this by restricting Black's strongest moves. If Black plays a forbidden move in a real tournament, they lose the game instantly. In online casual play, players typically agree to self-enforce these rules.
Black's Three Forbidden Move Types
- Double-Three (33): A move that simultaneously creates two open-three patterns. An "open three" is a line of three with both ends unblocked, one move from becoming an open four.
- Double-Four (44): A move that simultaneously creates two four-in-a-row patterns. Even one end being blocked counts — any two fours at once is forbidden.
- Overline: Six or more consecutive stones does not win for Black. Exactly five is required. White can win with an overline.
White Has No Restrictions
White can create double-threes, double-fours, and overlines freely. White can also win with an overline (six in a row). This asymmetry is what makes Renju strategically distinct and why it remains the rule set used in the World Renju Championship.
Tips for Playing Renju Online
- Agree on rules before the match: Since this platform uses the standard Gomoku engine, both players should confirm they're playing Renju rules.
- Double-check your move as Black: Before placing, quickly scan whether your stone creates two simultaneous open-threes or two fours. If yes, pick a different cell.
- Use White's freedom strategically: As White, you're not restricted — use double-four threats aggressively to put Black in difficult positions.
- Study forbidden move patterns: Recognizing 33 and 44 patterns quickly is a key skill in Renju. Practice spotting them in the positions that arise on the board.
Want to understand the full rule differences? Read our Gomoku vs Renju comparison or start with the Gomoku rules guide.
Prefer to Practice First?
Not ready for live opponents? Try Renju vs Computer to practice applying the forbidden move rules at your own pace before jumping into online matches.
Or switch to standard Gomoku online if you want to play without Renju restrictions.