What makes Expert so tough?
Expert 16×16 Hyper Sudoku gives you the smallest number of starter clues we use anywhere on the site. Auto Notes is essentially required, and you will need to spot patterns across the whole board, not just in one box at a time.
But every Expert puzzle on this site has exactly one answer, and you can solve it without guessing. Use logic, take breaks, trust your notes!
If Expert feels overwhelming, that is normal — even adults find it tough. Spend a few weeks at Hard 16×16 Sudoku first; the techniques are exactly the same, just with more starter numbers to lean on.
Techniques worth memorising
- 🔢 Hidden singles in every row, column and box — scan every time you place a new digit
- 🔢 Naked pairs and naked triples — two cells with the same two notes, or three cells with the same three notes, lock those numbers down
- 🔢 Pointing pairs: if a number in a 4×4 box can only go in two cells of one row, that number is locked on the row
- 🔢 Cross-hatching: pick one number, find every box it could be in, work out where it has to go
Expert solving routine
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Auto Notes first
Tap it the moment the puzzle loads. You will see every candidate digit at a glance.
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Sweep one number at a time
Pick a number — say 15. Find every box where it could go. Lock in any forced placements.
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Scan every region after every move
After every single placement, glance at the row, column and box you just affected. Hidden singles appear all the time.
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Hunt naked pairs and triples
After Auto Notes, look for two cells with the exact same two candidates on any row, column or box — those numbers are locked there.
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Place, repeat, win
Each placement narrows things down everywhere. Keep going until the board is full!
When you have mastered Expert
Once Expert 16×16 Hyper Sudoku feels comfortable, try our toughest Expert 9×9 sudoku. It is a different kind of challenge — a smaller board with tougher patterns — and the same long-thinking patience pays off.
Or try Hyper Sudoku for the original "Hyper Sudoku" — a 9×9 with four extra mini-boxes inside, X-Sudoku for puzzles with two diagonals, Killer Sudoku for puzzles with cage sums, or Jigsaw Sudoku for puzzles with wiggly regions instead of normal boxes.
Frequently asked questions
How long does an Expert 16×16 take?
Most kids who can solve Expert 16×16 finish in 45 to 90 minutes. Some take more than two hours — that is normal! There is no time limit.
Can I really solve Expert without guessing?
Yes! Every puzzle on this site has exactly one solution and was checked by computer to be solvable with logic alone. If your guess turns out wrong, just tap Undo.
What if I am really stuck?
Tap the Hint button — it fills one correct cell so you can keep going. Hints count in your stats, but they are there to help.
Is there anything harder than Expert 16×16 on this site?
No — Expert 16×16 Hyper Sudoku is the toughest puzzle we offer. Some grown-up sites have "Diabolical" or 25×25 levels, but those are designed for adult sudoku-club regulars, not kids.
Try other sudoku games
Different rules, same friendly board. Pick a sibling puzzle to play next.