Sudoku Ninja: Classic & Killer

Sudoku Labs

Contains adsIn-app purchases

About this game

Play Classic Sudoku and Killer Sudoku in one app! Enjoy 40,000 handcrafted sudoku puzzles, daily challenges, and relaxing offline play — a complete number puzzle experience for beginners and experts alike.

🥷 Two Sudoku Games in One
Why install two apps? Sudoku Ninja combines classic sudoku and killer sudoku, so you can switch between two popular logic puzzles anytime. Solve a quick easy grid on your commute, then take on a hard killer sudoku (also known as sumdoku, addoku, or sumoku) when you want a real brain workout.

📵 No Banner Ads — Ever
We hate interrupted thinking as much as you do. Sudoku Ninja shows no banners and no pop-ups while you solve. Ads appear only after you complete a puzzle, or when you choose to watch one for a hint. Your concentration stays unbroken from the first cell to the last.

🧩 Game Features
• 40,000 Sudoku Puzzles — endless content across both game modes
• Classic & Killer Sudoku — two number games in one app
• 5 Difficulty Levels — Easy, Medium, Hard, Expert, and Invictus for true masters
• Daily Challenges — solve the daily sudoku and earn unique rewards
• Offline Play — enjoy sudoku offline, anywhere, no wifi needed
• Magic Pencil & Autofill Notes — add and manage pencil marks instantly
• Fast Input Mode — built for experienced players
• Error Highlighting — customize how you detect and fix mistakes
• Auto-Save — pause any puzzle and resume anytime
• Cloud Sync — continue your game across devices
• Leaderboards — compete with players worldwide

🔢 How to Play Killer Sudoku
New to killer sudoku? It works like the classic number puzzle with one twist:
• Fill rows, columns, and 3x3 boxes with digits 1–9, just like classic sudoku
• Dotted lines mark “cages” — digits inside must add up to the number in the corner
• No repeats within a cage, row, column, or box

If you enjoy math puzzles like kakuro or kenken, killer sudoku will feel right at home. Every level is carefully balanced, so beginners learn fast while experts push their limits.

🧠 Brain Score
How sharp is your mind? Take a quick 7-minute brain test — pure visual logic, no math, no rules to memorize. Play daily for a week, then retake the test and watch your Brain Score climb. Track your progress across four skills: focus, speed, logic, and pattern recognition.

🥋 Ninja Mode
Experiment freely, like a sandbox for your brain. Mistakes are not counted or shown — perfect for testing strategies and learning. Apply your changes to the grid when ready, or roll back to your last checkpoint anytime.

☕ Coffee Mode
Set a time limit and race the clock! The harder it gets, the more bonus points you earn — perfect for quick, intense brain training sessions.

🎨 Customization & More
• Modern design with themes, colors, and fonts
• Gentle animations and a clean grid that helps you focus
• Share your progress with friends
• Regular updates with new puzzles every week

Whether you want to unwind with an easy number game or grind expert logic puzzles, Sudoku Ninja is made for every sudoku lover. Many puzzles are handcrafted by our team to guarantee a premium experience. Download now, train your brain daily, and become a true Sudoku Ninja!

Ratings and reviews

7/26/25 Update is terrible. I got this game earlier this year-it was perfect: a prompt to take you to a game center when you open it, then nothing else intrusive....until now. Imagine playing your first puzzle in the morning and when you fill that last box, even before you can move your finger away, the screen changes and you are hit with an ad for some military game with crazy gunfire-set off my anxiety...what a shame. And no way to exit it until it plays through. Total fail on this update😒👎

Very well done sudoku app. After a certain period you do get an ad after every game, but all ads show a timer and skip. None are intrusive during gameplay or open a browser to scam antivirus products. This developer is at least holding some integrity and respect for their customers. $12 flat price to remove ads rather than other shady developers that charge a monthly fee. -- Edit: After some time I find the ad practice doesn't change. This company values its customers'wishes.

I'd like to be able to see my mistake (it isn't showing despite having the "Show Mistakes" switch toggled on) . Also, the Undo function just stops working sometimes. Got to the point where I had to give up. I like the features otherwise but these features not working lead me to find an alternative.