XO Ultimate: Notebook Edition

Think you've mastered Tic-Tac-Toe? Try it on a bigger board against an AI that actually plans ahead.

XO Ultimate is a strategy puzzle game built on the classic pen-and-paper grid. Play 3x3, 4x4, or 5x5 boards, face up to three AI opponents, or pass the phone around with friends. The game works completely offline, so you can play anywhere.

BIGGER BOARDS, REAL STRATEGY
3x3 keeps the classic rules: first to line up three wins. On 4x4 and 5x5 boards, the game runs until the grid is full and points decide the winner:

- 3 in a row: 1 point
- 4 in a row: 3 points
- 5 in a row: 6 points
Every move is a tactical trade-off between building your long runs and blocking your opponent.

AN AI THAT THINKS
The AI uses Negamax search with alpha-beta pruning, iterative deepening, and custom heuristic evaluations across four distinct levels: Easy, Medium, Tough, and Impossible. Want chaos? Play against up to three bots at once, each challenging your territory.

PASS & PLAY FOR 2 TO 4 PLAYERS
Local multiplayer on a single screen. Pass the phone around with family and friends—no accounts, no internet, and zero setup required.

PLAY IN YOUR LANGUAGE
Enjoy XO Ultimate in your native tongue. Fully localized across 14 languages: English, Spanish (Español), Portuguese (Português), French (Français), German (Deutsch), Italian (Italiano), Russian (Русский), Hindi (हिन्दी), Indonesian (Bahasa Indonesia), Turkish (Türkçe), Filipino, Vietnamese (Tiếng Việt), Japanese (日本語), and Korean (한국어).

POST-MATCH ANALYSIS & TACTICAL REVIEW
Review your match move by move. Each turn is audited for Brilliant moves, Solid positional play, and costly Mistakes or Blunders. In Pass & Play, an Intelligence Rating report benchmarks how players performed. Enjoy a free daily analysis every day, or unlock extra reviews with optional rewarded ads.

BRAIN SCORE & MASTERY TIERS
Every match against the AI updates your Brain Score, an ELO-style rating that dynamically rises and falls with your performance and opponent difficulty. Start at 700 and climb through seven tiers: Beginner (700–899), Casual, Skilled, Expert, Master, Grandmaster (1700–1799), and Legend 👑 (1800+).

STREAKS AND UNDOS
Play one match a day to keep your daily flame going. Each game against AI includes one Undo to rewind accidental slips, and you can stock up on more through rewarded ads. Maintain a 7-day streak to earn 2 bonus Undos every time you refill.

HAND-DRAWN LOOK AND FEEL
A tactile notebook paper and ink aesthetic with clean light and dark modes, pencil sound effects, and subtle haptic feedback. Clean, distraction-free, and easy on the eyes.

PRIVACY & FAIR PLAY
Your game progress, ledger stats, and preferences stay strictly on your device. XO Ultimate does not collect or sell your personal data. Ads are served transparently via Google AdMob with full GDPR/CCPA consent controls on first startup.

GOOD FOR Puzzle fans, chess and board game lovers, casual players looking for a quick mental workout, and anyone who found regular Tic-Tac-Toe too simple.

Download XO Ultimate and see how high your Brain Score can climb.