What’s tougher about Hard?
Hard Shape Sudoku starts with roughly half the shapes of an Easy puzzle. A single row scan rarely places anything — you’ll need to combine rows, columns AND the box rule on nearly every move.
Don’t rush! Most Hard shape puzzles take 7–14 minutes when you’re used to them, and longer when you’re still learning.
If you haven’t played the easier levels yet, do a few rounds at Medium Shape Sudoku first to make sure the basic strategies (box scan, twin sweep, same-shape squad) feel automatic.
Two real solver tricks
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Naked pairs
If two squares in the same row, column or box can only be a triangle or a circle, no other square in that group can be a triangle or a circle. Erase those candidates from the rest of the group to free up moves.
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Hidden singles in a box
Scan the candidate notes in a single 2×3 box. If a shape only appears as a candidate in one square, it must go there — even if the row and column candidates are still busy.
Hard game plan
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Step 1
Tap Auto Notes to fill every empty square with its candidate shapes.
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Step 2
Look for any square with only one candidate — place it immediately.
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Step 3
Scan each box for hidden singles.
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Step 4
Hunt for naked pairs in rows, columns and boxes, and erase those shapes from the rest of the group.
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Step 5
When stuck, tap Hint — then keep going!
Common Hard mistakes
- ⏩ Going too fast. Hard punishes guesses — a wrong shape ripples through three groups at once.
- 📝 Forgetting to erase a candidate after placing a shape. Always update notes.
- 🔢 Only using one rule. Rows, columns AND boxes all matter on Hard.
- ✅ Skipping Check. If something feels stuck, a wrong shape earlier in the puzzle is usually the cause.
Frequently asked questions
Is Hard Shape Sudoku too tough for kids?
Hard is really meant for kids who already enjoy puzzles. If it feels too tough, jump back to Medium — there’s no rush.
Can I solve a Hard puzzle without guessing?
Yes — every puzzle on this site has exactly one solution and is designed to be solved with logic. The Hint button always reveals a correct square if you really need it.
How does Hard Shape compare to Hard 6×6?
They’re the same difficulty. Many kids find the shape version slightly faster because the brain spots bold icons quicker than it reads digits.
Try other sudoku games
Different look, same friendly logic. Pick a sibling puzzle to play next.