Sudoku

How to play Sudoku

Sudoku is played on a 9×9 grid divided into nine 3×3 boxes. Some numbers are given at the start. Your task is to fill every empty cell so that each row, each column and each 3×3 box contains the digits 1 through 9 exactly once. Tap a cell, then tap a number (or use your keyboard). Every puzzle generated here has exactly one solution reachable by pure logic — no guessing ever required.

Solving techniques for beginners

• Scan for singles. Find rows, columns or boxes that are nearly full — often only one digit can fit the remaining cell.
• Cross-hatch. Pick a digit, then check where it can legally go inside a box after eliminating rows and columns that already contain it.
• Work the crowded areas first. The more givens around a cell, the fewer candidates it has.
• On harder puzzles, think in pairs. If two cells in a unit can only hold the same two digits, those digits can be eliminated from every other cell in that unit.

Why Sudoku endures

Modern Sudoku was popularized in Japan in the 1980s and became a worldwide phenomenon in 2005. Unlike word games, it needs no vocabulary — just logic — which makes it one of the most universal brain exercises ever invented. Regular solvers often report better concentration and a satisfying sense of daily accomplishment.