Mono Grid Duel is a monochrome three-in-a-row game in the browser: play on a 3x3 grid vs CPU (Easy, Normal, or Hard minimax) or hotseat 2P. Click cells or use keyboard numpad and arrows. About ~64 KB after Play, no install, no account.
Prefer a paddle reflex duel from another genre? Try Mono Paddle Duel.
Grid duel from the open-source Cursor Arcade tictactoe module (MIT). About ~64 KB downloads once from this site when you press Play. Win counts stay in your browser.
Click cells or use numpad 7-8-9 / 4-5-6 / 1-2-3. Arrows move cursor; Enter or Space places. R restarts. Settings: 1P vs CPU or 2P hotseat.
Mono Grid Duel
The goal in Mono Grid Duel is simple: line up three of your marks in a row, column, or diagonal before your opponent does. When you reach three in a row the winning line flashes, so the result is easy to read at a glance.
Key features
- Draw detection is built in, so a full grid with no winning line is called a tie instead of leaving the round open.
- Choose how hard the CPU plays: Easy moves at random, Normal makes a deliberate mistake about a third of the time, and Hard uses perfect play you cannot beat - against it a draw is the most you can force.
- In 2P hotseat the first move alternates each round, so neither player keeps the opening advantage across a session.
- Pick your mark as X or O, and a separate win tally is kept for Easy, Normal, and Hard so you can see how you fare at each level.
Saved progress
Your win counts stay in this browser, saved under the key ftol:monogridduel:storage, so the tally is still there the next time you come back.
Open source and privacy
The game is adapted from the open-source Cursor Arcade tic-tac-toe module under the MIT license, and it ships that project's LICENSE and CREDITS. Nothing is uploaded, and play stays on your device.
For more free browser games, open the games hub.
Frequently Asked Questions
What does Mono Grid Duel do?
It is a three-in-a-row game on a 3x3 grid. Play vs CPU on Easy, Normal, or Hard (full minimax on Hard), or hotseat 2P on one keyboard. Mouse clicks and keyboard numpad or arrows both work.
Does it work on a phone?
The page loads on phones and you can tap cells. Keyboard shortcuts (numpad, arrows) need a desktop or laptop for full control.
Is anything saved in my browser?
Yes. Mode, difficulty, player mark, and win counts use localStorage key ftol:monogridduel:storage via the settings stub. Reset all high scores clears bests from Settings. Nothing is uploaded.
How big is the download?
About ~64 KB of HTML, CSS, and JS after you press Play. The browser caches it for later visits on the same device.
How do I play?
Click an empty cell or use numpad keys 7-8-9 / 4-5-6 / 1-2-3. Arrow keys move a cursor; Enter or Space places your mark. R restarts. Open Settings for 1P vs CPU, difficulty, and X or O mark.
Is this open source?
Yes. It is adapted from the tictactoe module in Cursor Arcade by flancast90 (flancast90/cursor-arcade-games) under the MIT license. This site build stubs the VS Code webview API and ships LICENSE and CREDITS.