Gomoku (Omok) Korean Standard Rules: No Double-Three, No Overline
The standard rules used in Korean online Omok: double-three is forbidden for both players, double-four is allowed, and six or more in a row does not win.
Play Gomoku (Omok) Online Free vs AI
Play Gomoku against the AI right away, no sign-up needed. We use the Korean standard rules: double-three is forbidden for both Black and White.
How to play Gomoku (Omok)
- Goal: Be the first to line up five of your stones horizontally, vertically or diagonally.
- Turns: Black moves first. Players take turns placing one stone on an empty intersection. Stones never move or get removed.
- Board: A 15×15 grid of intersections.
- Draw: If the board fills up with no winner, the game is a draw.
Rules on this site: Korean standard rules
We use the standard rules common in Korean online Omok.
- No double-three: You may not play a move that creates two or more open threes at once. This applies to both Black and White. Forbidden points are marked with ✕.
- Double-four is allowed.
- Exactly five wins: Six or more in a row (an overline) does not win.
- Five comes first: A move that completes five is always allowed and wins, even if it also makes a double-three.
How we judge it: an open three is three stones that become an open four with one more move, including split threes (●●·●). We do not check whether the point that would make the open four is itself forbidden.
Useful terms
| Term | Meaning |
|---|---|
| Open three | Three stones with open ends that become an unstoppable open four with one more move |
| Four | Four stones that make five with one more move. Your opponent must block it |
| Open four | Four stones that make five at either end. It cannot be blocked in one move |
| Four-three | A move that makes a four and an open three at once, a classic winning attack |
Tips for beginners
- Block your opponent's four before anything else, or you lose on the next move.
- Block open threes early. Once they become an open four, it is too late.
- Keep your stones close together so they can grow in several directions.
- Aim for a four-three: while your opponent blocks the four, the three becomes an open four.
- On this site White cannot play double-threes either. Spotting your opponent's forbidden points makes defending easier.
FAQ
- Do I need an account?
- No. Open the page and start playing the AI right away.
- Is my game saved?
- It is saved automatically in this browser, so you can reload or come back later. It is not shared across devices.
- Can I play with Renju rules?
- Only the Korean standard rules are available for now. A Renju option is planned.
- It is hard to tap the right point on my phone.
- Press and hold on the board to open a magnifier above your finger. Slide to adjust, lift to place, or release off the board to cancel.