How to Play Mono Grid Duel - Step by Step
The Mono Grid Duel page loads a ~64 KB three-in-a-row grid in an iframe. Play vs CPU or hotseat 2P. Press Play to start.
Step 1 - press Play
Press Play to inject the iframe (~64 KB). The engine auto-opens the grid duel. Upstream is the Cursor Arcade tictactoe module by flancast90 (MIT).
Step 2 - pick mode
Open Settings for 1P vs CPU or 2P hotseat. Choose CPU difficulty Easy, Normal, or Hard. Pick your mark X or O in 1P mode.
Step 3 - place marks
Click an empty cell or use the numpad layout matching the grid. Arrow keys move a cursor; Enter or Space commits. CPU responds on its turn in 1P mode.
Step 4 - win or draw
Three in a row wins. Full grid with no winner is a draw. Win counts save per difficulty under ftol:monogridduel:storage.
Step 5 - restart
R restarts the board. Esc returns to the one-game menu. Reset all high scores clears win counts from Settings.
| Setting | Value | Notes |
|---|---|---|
| Download | ~64 KB | arcade shell + tictactoe + CSS |
| Grid | 3 x 3 | three in a row wins |
| Saves | localStorage | ftol:monogridduel:storage |
| Server calls | 0 | Client-side only |
See when to play, comparisons, and Mono Paddle Duel.
Why trust these tools
- Ten-plus years of web tooling. The freetoolonline editorial team has shipped browser-based utilities since 2015. The goal has never changed: get you to a working output fast, without an install.
- No install, no sign-up. Open a tool and get a working output in seconds - nothing to download and no account to create. Tools that need heavy processing run it on our service, so even a low-powered machine gets the job done.
- Analytics stops at the page view. We measure which pages get visited, not what you type or upload inside a tool. There is nothing to sign in to and no profile is attached to your input.
- Open-source core components. The processing engines underneath (libheif, libde265, pdf-lib, terser, clean-css, ffmpeg.wasm, and others) are public and audit-able. We link to each one in its tool page's footer.
- Free, with or without ads. All tools are fully functional without sign-up. The Disable Ads button in the header is always available if you need a distraction-free run.