The rules
- Sudoku with irregular box shapes instead of square boxes.
- Each row, column and box must hold every number exactly once.
- Tap a cell and type a number.
Getting started: Follow the irregular boxes closely — a nearly full box often reveals the next number.
Step by step
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1Here is the puzzle. The fixed numbers are given.
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2The only cell in its row, column or box where 8 fits — so 8 goes here.
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3The only cell in its row, column or box where 3 fits — so 3 goes here.
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4The only cell in its row, column or box where 3 fits — so 3 goes here.
4 more steps in this walkthrough — the full step-by-step solve is a Pluss feature. About Pluss →
Real puzzle no. 378, solved step by step by the logic solver.
Common questions
Can I play right in the browser?
Yes. Pick a Codoku puzzle and solve it on screen — press “Check” to see if you are on track, and “Hint” if you get stuck. You can also print it.
Can I link to a specific puzzle?
Of course. Every puzzle has a number, and you can link straight to it: puzzles.flogvit.com/eng/codoku?nr=100. Replace 100 with the puzzle number — handy for challenging a friend with the very same puzzle.
Can I print the puzzles?
Yes. Each type has a print sheet for one or four puzzles with the answers on a separate page.
Are the puzzles free to use?
Yes, this is a free service. If you want to publish the puzzles elsewhere you must arrange it first — see copyright.