What makes Expert so tough?
Expert Space Sudoku gives you about nine starter icons — the smallest clue count we use on this game. Every placement has to come from combining the row, column and 2×3 box rules at once.
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’s normal — even adults find it tough. Spend a few weeks at Hard Space Sudoku first; the techniques are exactly the same, just with one or two more givens.
Techniques worth memorising
- 🔵 Hidden singles in every row, every column, every box
- 🟡 Naked pairs and naked triples across all three group types
- 🟢 Pointing pairs: if an icon in a box can only go on one row or one column, it’s locked out of the rest of that row/column
- 🟣 Box/line reduction — same as classic sudoku, just on the 6×6 space board
Expert solving routine
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Auto Notes first
Tap it the moment the puzzle loads. Every empty square shows its candidates as tiny space icons.
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Scan by box
Each 2×3 box has only six squares. Spot any hidden singles and place them.
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Hunt naked pairs
Look for two squares with the same two candidate icons in any row, column or box — those icons are locked into those squares.
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Watch for pointing pairs
If an icon’s candidates inside one box all sit on the same row, you can erase that icon from the rest of the row.
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Place, repeat, win
Each placement narrows the candidates for the rest of the board. Keep going until every square is filled!
When you’ve mastered Expert
Once Expert Space Sudoku feels comfortable, try our toughest classic 9×9 sudoku or give Killer Sudoku a go — cage sums add an arithmetic twist on the same rules.
Or try Circle Sudoku for the same 1–6 logic on a round board, or Jigsaw Sudoku where the boxes are wiggly jigsaw shapes. Very different looks, all built on the same "one of each in every line" idea.
Frequently asked questions
How long does an Expert Space Sudoku take?
Most kids who can solve Expert finish in 10 to 20 minutes. Some take longer — that’s normal. There’s 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’m really stuck?
Tap the Hint button — it fills one correct square so you can keep going. Hints count in your stats, but they’re there to help.
Is there anything harder than Expert Space Sudoku?
On this site, Expert is the toughest space puzzle. Try our toughest 9×9 sudoku next, or Killer Sudoku for an arithmetic-flavoured challenge.
Try other sudoku games
Different look, same friendly logic. Pick a sibling puzzle to play next.