Classic is where most people play Sudoku Royale: unlimited sudoku puzzles, one after another, at six difficulty levels from Easy to Extreme. There are no ads between puzzles, no daily cap, no lives, and no countdown. You open the Play tab, pick a level, and solve. This guide covers how the levels work and unlock, what help you get when you are stuck, and how to use unlimited practice to actually improve.
How Classic works
Tap Play on the Play tab and a puzzle loads at the level you last chose. Every puzzle has exactly one solution. A timer counts up in the corner so you can chase a personal best, but nothing happens when it runs long. Mistakes are counted and shown on the result screen, and they never end the game or add a penalty.
When you finish, the result screen shows your time, your mistakes, and the shurikens you earned. Beat your best time for that level and you get confetti. Then tap Next Puzzle and keep going. If you leave in the middle of a board, the app saves it, and the Play button changes to Resume so you can pick up where you stopped.
Classic puzzles are downloaded ahead of time and cached on your phone, so they play offline on a plane or the subway. Hints need a connection.
The six difficulty levels
Each level is defined by the hardest technique a puzzle may need and by how much searching it takes to find each move. The number of starting clues is not part of the grade.
| Level | Hardest technique it may need | How to unlock |
|---|---|---|
| Easy | Naked singles | Open from the start |
| Medium | Hidden singles | Open from the start |
| Hard | Pointing and claiming | Solve 2 Medium puzzles |
| Expert | Naked pairs, hidden pairs, X-Wing | Solve 4 Hard puzzles |
| Master | Triples, Swordfish, XY-Wing | Solve 10 Expert puzzles |
| Extreme | Simple colouring, Jellyfish | Solve 14 Master puzzles |
The unlock path is short on purpose at the bottom and longer at the top. Two Medium solves are enough to show you are ready for Hard, but Master and Extreme ask for real practice at the level below, because the techniques they need take time to learn. Our full guide to sudoku difficulty levels explains each technique tier in more depth.
How long a puzzle takes
From solves in the app, a typical Easy board has about 44 empty cells, Medium about 51, and Hard about 56. The median player fills one empty cell every 11 seconds or so, and that pace stays fairly steady across levels. So a typical Easy puzzle takes around 8 minutes, a Medium around 9 or 10, and a Hard one longer, because the harder moves take extra time to find. Fast players run at about 7 seconds per cell. If you want to know where you stand, divide your time by the number of empty cells.
Try Sudoku Royale
The classic sudoku you know, without the ads, the pop-ups, or the clutter. A fresh Daily Challenge, unlimited practice with no timer, and technique drills. When you want a rush, race 2 to 18 players on one shared grid.
Download Sudoku Royale: Free on iOSHints that teach
If you go 90 seconds without a correct entry, a light bulb appears. Tap it and the app highlights the next cell you can solve and tells you which technique finds it, for example a hidden single in that row. A Learn button opens the lesson for that technique in the Learn tab. If the next move needs a technique beyond the basics, the hint says so.
This is different from hints that just fill in a number. You still place the digit yourself, and you come away knowing why it goes there. Over a few weeks the hints show up less often, which is the point.
Tools on the board
Notes mode lets you pencil in candidates, and a Highlight Same Number setting lights up every copy of the digit you select, which makes scanning faster. The board comes in light and dark themes. For the full picture of how to use candidates well, see our guide to sudoku pencil marks.
How to practise so you improve
- Play one level above comfortable. If Medium puzzles never need a hint, move to Hard, even if your times get slower for a while.
- Track time per empty cell, not total time. It lets you compare an Easy solve with a Hard one and see whether you are getting faster.
- Read every hint. When the bulb names a technique you do not know, open the lesson. That is the technique holding you back at this level.
- Keep sessions short. Two or three puzzles a day do more than one long session a week. The Daily Challenge is an easy anchor for that habit.
- Use Journey for the jumps. If you are stuck between two levels, the Journey chapters teach the technique that separates them, one step at a time.
Practice and the rest of the app
Every correct cell in Classic earns shurikens toward your weekly belt, and harder levels earn more per cell. Classic has no effect on the skill rating used by the optional live matches. For how Classic fits with the Daily Challenge, Journey, and everything else, see the overview of Sudoku Royale.
Frequently Asked Questions
Is there a limit on how many puzzles I can play?
No. Classic gives you unlimited puzzles at every level you have unlocked, with no daily cap, no lives, and no ads between puzzles.
What difficulty levels does Sudoku Royale have?
Six: Easy, Medium, Hard, Expert, Master, and Extreme. Easy and Medium are open from the start. Hard unlocks after 2 Medium solves, Expert after 4 Hard solves, Master after 10 Expert solves, and Extreme after 14 Master solves.
Do mistakes end the puzzle?
No. In Classic, mistakes are counted and shown on the result screen, but there is no limit and no time penalty.
Can I play sudoku offline in Sudoku Royale?
Yes. Classic puzzles are cached on your phone and play without a connection. Hints, the Daily Challenge, and leaderboards need to be online.
How do hints work?
After 90 seconds without a correct entry, a light bulb appears. Tapping it highlights the next solvable cell and names the technique that finds it, with a button to open the lesson for that technique.
How long does a sudoku puzzle take?
In Sudoku Royale, a typical Easy puzzle has about 44 empty cells and takes the median player around 8 minutes. Medium boards have about 51 empty cells and Hard about 56, and harder moves take longer to find.