Samurai Sudoku · 21×21
Sudoku, doubled.
Five grids. One battlefield.
A 21×21 Samurai Sudoku board where five 9×9 grids overlap. Play solo or duel a friend in real-time Battle mode.
- App Store
- Puzzle Games
- 4+
- iOS 18+
- No ads
- No trackers
Five 9×9 grids share four 3×3 blocks. Solve them all.
- 01
Tap a cell
Empty squares wait for you. Tap to focus.
- 02
Pick a digit
1–9 keypad pops up. Wrong guesses end Battle mode instantly.
- 03
Watch the grids align
Numbers solved in one grid help unlock the next.
Two ways to play.
Sharpen your solve alone, or put it on the line against a friend.
Solo
Train your sword.
- Easy, Medium, Hard, Expert
- Three cloud save slots — pick up where you left off across devices
- Personal best timer and six warrior ranks (Ashigaru Apprentice → Emperor)
Battle
Duel a friend in real time.
- Same puzzle, same board, both players
- Live opponent moves stream over WebSocket
- First wrong move loses · highest score on completion wins
- Invite by code or pick a friend from your list
Take a look around
Beautiful on every screen.
Swipe through what you get the moment the download finishes.
Solo A board twice as wide
Five 9×9 grids share four 3×3 blocks. Every number you place ripples through the rest.
Battle Race a friend in real time
First wrong move loses. Highest score on completion wins. Live moves stream over a secure WebSocket.
Victory Win with honor
Cinematic samurai victory and defeat screens — brush calligraphy, a katana slash and falling sakura.
Settings Play your way
Conflict hints, row & column highlights, undo and Face ID sign-in — every assist is optional and off by default.
Theme Hand-painted wallpapers
Pick a preset or upload your own. Pinch, pan and crop until the battlefield feels like yours.
Sign in Face ID, one tap return
Sign up with email once. After that, Face ID drops you back in faster than the timer can start.
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Built for puzzle lovers
Everything that respects your time.
No nags, no upsells, no surprise paywalls — just the parts of Sudoku you actually want.
Face ID sign-in
Skip the password. Two taps and you’re in.
Cloud save slots
Three slots, every device. Pause on iPhone, finish on iPad.
Five hand-painted wallpapers
Plus upload up to five of your own. The battlefield feels like yours.
Six warrior ranks
From Ashigaru Apprentice to Emperor. Promotions every few hundred wins.
Global leaderboard
Weekly, monthly and all-time. See where the best players stand.
No ads, no trackers
Zero advertising IDs, zero third-party SDKs. Only what the game needs.
Pause anytime
Tap pause and the grid hides itself. Resume when you’re ready.
Smart conflict highlights
Optional. Toggle them on while you learn, off when you’re ready to compete.
Free to play
Every mode, theme and wallpaper unlocked from day one.
Early testers don’t talk smack quietly.
Swipe to read more →
Questions, answered.
Is Battle Sudoku free?
Yes. The full game is free. There are no ads and no trackers.
Does it work offline?
Solo mode works offline. Battle mode needs a network connection because the server arbitrates moves between both players.
Do I need an account?
Yes — a free account is needed to sync saves and to play Battle. Sign up with email; password reset and Face ID quick-sign-in are supported.
Can I delete my account?
Yes. Profile → Delete Account permanently removes your profile, friends, matches, statistics and uploaded photos within 24 hours.
What about my friends' privacy?
We don't read contacts. The only friend list is the one you build inside the app.
Which iOS versions are supported?
iOS 18 and later. iPhone and iPad.