How a game proceeds
Black moves first
Black normally opens on an intersection of a 15×15 or 19×19 board.
One stone per turn
Black and White alternate on empty intersections. Occupied points cannot be used.
Connect five
The first player to connect stones horizontally, vertically or on either diagonal wins.
Check ruleset exceptions
Freestyle accepts overlines, while exact-five and Renju judge them differently.
RULESETS
Compare three rulesets
| Ruleset | Black wins | White wins | Forbidden | Best for |
|---|---|---|---|---|
| Freestyle | Five or more | Five or more | None | Beginners and casual games |
| Exact five | Exactly five | Exactly five | None | Overline-aware calculation |
| Renju | Exactly five | Five or more | Black: 3×3, 4×4, overline | Balanced competitive play |
RENJU
Moves forbidden to Black in Renju
The restrictions reduce the first-player advantage. They apply to Black, not White.
Creates two open threes
One move produces two separate open-three lines that can each grow into an open four.
Creates two fours
One move creates two immediate winning threats, so a single defensive move cannot stop both.
Overline
Six or more consecutive black stones. In Renju, Black must make exactly five.
ORDER MATTERS
A practical adjudication order
- Check whether the last move creates the selected winning condition.
- For Black under Renju, check overline and compound forbidden patterns.
- If the board is full with no winner, declare a draw.
GLOSSARY
Pattern glossary
- Open four
- Four stones with both winning endpoints open; it cannot be defended in one move.
- Closed four
- A four pattern with only one point that completes five.
- Open three
- A three-stone formation that can become an open four in one move.
- 4-3 fork
- A move that creates a four and an open three at the same time.
- Overline
- Six or more consecutive stones of the same color.
FAQ
Rules FAQ
Do diagonal lines count?+
Yes. Both diagonal directions count exactly like horizontal and vertical lines.
What if Black makes five and a forbidden pattern at once?+
Official Renju edge cases can be intricate. Separate an exact five from an overline and follow the ruleset or referee used by the event.
Why is only Black restricted?+
Black moves first and has a large initiative advantage in unrestricted play. Renju uses forbidden moves and opening procedures to reduce that advantage.
PUT IT INTO PRACTICE