Sudoku

Each puzzle gives you a 9×9 grid, partially filled with numbers, and one clear goal: place digits 1 through 9 so that every row, every column, and every 3×3 box contains each number exactly once. No guessing required — just careful deduction, one cell at a time. The built-in hint system nudges you when you're stuck without giving the whole game away.

Multiple difficulty levels mean you can ease in with a sparse but manageable grid or push yourself with a near-empty board that demands serious backtracking. It's one of the most well-tested logic formats ever designed, and this version keeps it clean and distraction-free. If you enjoy grid-based games that reward patience over reflexes, this is worth a look. Launch Nonogram covers similar ground if you want a visual twist on the same fill-the-grid format.

The full 9×9 grid takes up a fair amount of screen space, so a tablet or desktop will give you more comfortable cell targets than a small phone. No account needed — just pick a difficulty and start filling.