Renju: Rules and How to Play
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.
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 and scoring
- 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.
Defaults on this site
| Item | Default on this site |
|---|---|
| Players | 2 players (set automatically by the party size) |
| Turn time limit | None by default (the host can set 30 or 60 seconds) |
| If someone drops mid-game | Reopening on the same device returns you to your seat. If you do not return, the CPU plays in your place. |
| Draws | In ranked play, a draw counts as halfway between a win and a loss for your rating. |
| Source of the rules | Based on the standard reference rules |
Rules supervised by Qdan, Inc. (based on the standard reference rules)
House rules
Defaults follow the standard reference rules. The party can change these.
| 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 |
Terms
- Forbidden move
- A move black alone cannot make without losing: overline, double four, double three.
- Three
- A line that becomes a straight four (a four with two points that make five) with one more stone.
- Four
- A line that becomes five with one more stone.
- Overline
- Six or more in a row. White wins with it; black loses for it.
- Opening rule
- A procedure for the first few moves. The default is Taraguchi-10 (place-five-alternate).
FAQ
What are a double three and a double four?
One move that makes two open threes (double three) or two fours (double four) at once. Both are forbidden for black only.
What if a move makes five and looks like a double three?
It can still be played, and wins immediately — five always takes priority over the restrictions.
What is an overline?
Six or more stones in a row. White wins with it; black loses for it.
Does this differ from the Japanese Renju Association's rules?
The forbidden moves and outcomes are the same. The difference is procedural: over the board, white must claim a forbidden move; here the server judges automatically.
Can a game be drawn?
Yes, if the board fills or both players pass in a row.
Can I show coordinates?
Yes, in the party settings. It shows a–o and 1–15 on the edge of the board without changing the rules.
Play now with these rules
Last updated 2026-09-23 · Run by Qdan, Inc.