Renju
Renju is a board game for 2 that takes about 15 minutes: gomoku plus forbidden moves, where black alone loses for a double three, double four or overline. Free. In-browser. No account.
Play over time
Renju in 30 seconds
- Set upA 15×15 board. Black plays first, in the centre point.
- Take turnsPlace one stone on a crossing. The first few moves follow an opening rule (default: Taraguchi-10) that limits where and who plays. In Taraguchi-10, before each of the first 6 moves you decide which of you plays it (“Opening move N of 6” on screen).
- Forbidden movesBlack alone loses instantly by making a double three, a double four or an overline. White is never restricted.
- WinThe first to line up exactly five wins. White also wins with six or more in a row.
At a glance
| Item | This game |
|---|---|
| Players | 2 players |
| Play time | About 15 min |
| Type | Board |
| Ranked play | No |
| Practice against the CPU | Yes |
| Price | Free (no account needed) |
| Rights holder | A public-domain classic game |
| Last updated | 2026-09-23 |
How to play Renju online with friends
- Tap "Play with friends"A party is created with a 6-character code. No account is needed.
- Send a link or QR codeShare it on LINE, or just read the code aloud.
- Everyone opens it in a browserOnce 2 players have joined, the host taps "Start".
Rule highlights
Setup, play, winning, and house rules
Setup
- Two players. You need a 15×15 board (fifteen lines each way) and black and white stones. The board size does not change.
- Black plays first, white second. Black's first stone always goes in the centre point.
- The opening few moves follow an opening rule. The default, Taraguchi-10, alternates who decides — play the next move yourself, or let your opponent — while the playable area grows a little each time. Pro rule (26 openings), Soosõrv-8, and free play (black is favoured, no restriction) are also available.
How to play
- Starting with black, take turns placing one stone on any empty crossing. Passing is a last resort as the board fills.
- A stone never moves again and can never be captured.
- Black alone is restricted from three moves: an overline (six or more in a row), a double four (one move making two open fours), and a double three (one move making two open threes). A forbidden point is marked with an ×; tapping it once asks you to confirm, and tapping again plays it — and loses instantly. White is never restricted.
- A move that makes exactly five is always allowed and wins immediately, even if it also looks like a double three or double four (five always takes priority).
- A setting can show coordinates (a–o, 1–15) on the edge of the board. It does not change the rules.
Winning
- The first player to line up exactly five wins, in any direction.
- White also wins with six or more in a row (an overline). Black loses instantly for an overline, even one that contains a line of exactly five.
- If black plays a double three, double four or overline, white wins on the spot.
- You may resign at any time; resigning loses the game.
- The game is a draw if the board fills, or if both players pass in a row. If black has no legal point left except forbidden ones, the game continues with a pass rather than ending.
- Renju is gomoku with forbidden moves and opening rules added for competitive play. To try just the forbidden moves, Gomoku's own “forbidden moves” setting offers the same three restrictions without the opening rules.
House rules
| Name | Description | Default | Changeable |
|---|---|---|---|
| Opening ruleOpening ruleBlack has a strong first-move edge in renju, so the first moves follow a set procedure during which the players can change who takes black. The pro rule is the simplest: the tentative first player places three stones, then the other player picks black or white. Taraguchi-10 and Soosõrv-8 are official tournament rules with longer procedures. Free play only puts black's first stone in the centre, so black is well ahead. | How the first few moves are decided. Choose Taraguchi-10 (default), Soosõrv-8, the pro rule, or free play. | Taraguchi-10 | Yes |
| Forbidden move marks | Show an × on black's forbidden points on black's turn. The rules do not change. | On | Yes |
| Show coordinates | Show coordinates (a–o, 1–15) on the edge of the board. The rules do not change. | Off | Yes |
| Swap who startsSwap who startsThe tentative first player is the one who places the first stones in the opening procedure. Because colours can be chosen again along the way, they do not necessarily end up with black. With this on, the tentative first player alternates each game. | Swap who plays black first after each game. | On | Yes |
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FAQ
How many players?
Two.
How is it different from Gomoku?
Black alone is restricted (double three, double four, overline) and loses instantly for one; there is also an opening rule for the first few moves. White wins even with an overline.
What happens if black plays a forbidden move?
White wins immediately. Unlike Gomoku's own “forbidden moves” setting, which simply blocks the point, Renju lets you play it — and you lose the moment you do.
Which opening rule is used?
Taraguchi-10 by default. A party can switch to Soosõrv-8, the pro rule, or free play.
Can I practise alone?
Yes. Press Play vs CPU to play against the computer.
Can I play on a phone?
Yes. No app is needed — just open it in a browser. You can join the same party as people on a PC or tablet.
Can two people play?
Yes. This game supports 2 or more players.
Can we play without being online at the same time?
Yes. Choose “Turn-based (told each turn)” and you can make one move whenever you like. We tell you when it is your turn. A table ends automatically, with no winner or loser, after 45 days without a move.
Rights holder and physical edition
This is a public-domain classic game. The rules follow the standard reference rules.
Related games
Same type (Board)
Same player count
Last updated 2026-09-23 · Run by Qdan, Inc.