How to play
- Choose an open square for your mark.
- Block an opponent who can complete a line on the next turn.
- Create a fork when possible so two winning lines are available.
What this game practices
A useful first strategy game because the complete state is small enough to discuss. Experienced play often ends in a draw, which is evidence of correct defense rather than failure.
How we checked it
Open-source HTML5 game reviewed in the local coolmath build for startup, primary controls, restart flow, narrow-screen fit, console errors, failed requests, and third-party network activity. Upstream telemetry is disabled in this self-hosted copy.
Open-source license and attribution
This self-hosted game is adapted from Web Games by mashukui and distributed under the MIT License. coolmath disabled upstream telemetry and records its local changes in the open-source notices.
Reviewed by coolmath Editorial Team · Updated 2026-10-09