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Four difficulty tiers that scale up automatically, forever — every puzzle is generated fresh with exactly one guaranteed solution
Sudoku is more than a number puzzle — it demands sequential logical reasoning and working memory, because you have to keep the row, column and box constraints active in your head with every move. What regular play reliably improves is your Sudoku itself: you spot patterns faster, plan further ahead, and finish in less time — a real gain you can watch in your own numbers. Whether it carries over to concentration in work or study is far less certain, and we won't promise what we can't deliver.
Fill the 9×9 grid with the numbers 1 to 9 so that no number repeats within any row, any column, or any 3×3 box. Each puzzle starts with a set of fixed numbers you cannot change, and your job is to deduce the rest through logic alone — never guesswork.
Yes. This Sudoku runs straight in your browser on mobile and desktop with nothing to install. Play free without signing up, or sign in to save your score and best times and sync them across any device.
There are four tiers: Easy, Medium, Hard and Expert. You start on Easy, and five wins on any tier unlocks the next one. Within each tier the difficulty ramps up gradually as your win count grows, across an unlimited number of puzzles — so you will never hit a final level.
How to Play Sudoku: A Beginner's Guide That Actually Clicks — the one rule behind the whole game, two techniques that carry you through most puzzles, and the five habits that slow beginners down.