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Arrow keys: select cell · 1–9: digit · N: notes · Delete: erase · Ctrl/⌘ Z: undo
Sudoku is one of the most popular logic puzzles in the world. The goal is to fill a 9x9 grid so that every row, every column and every 3x3 box contains the digits 1 to 9 exactly once. Playing Sudoku regularly is a great way to train concentration, patience and structured thinking.
Sudoku is a logic puzzle based on placing numbers in the right positions. It does not require advanced math. The challenge comes from elimination, pattern recognition and careful reasoning.
At the beginning, some cells are already filled in. Your task is to complete the remaining empty cells until the full grid is solved. A number is valid only if it does not already appear in the same row, column or 3x3 box.
A move is invalid ifA few simple habits can make the puzzle easier to read and help you find safe moves more quickly.
Rows, columns and boxes that already contain many digits often reveal the next move fastest.
A cell often becomes obvious only when you combine all three restrictions at the same time.
When several numbers are still possible, notes help you stay organized and avoid random mistakes.
With practice, you will start spotting structures that let you eliminate options quickly and narrow down the right place.
Once the basic rules feel natural, Sudoku becomes a calm and rewarding flow. Starting with easy puzzles is the best way to build confidence.
Start with an easy Sudoku. Focus first on rows, columns and 3x3 boxes that already contain many digits, because those usually reveal the next safe move fastest.
Move to another area of the grid and compare row, column and box again. It also helps to use notes for candidates instead of guessing.
Levels are based on the solving techniques required: naked singles, hidden singles, candidate eliminations, and finally hidden pairs or X-Wing. New puzzles are checked against these levels and can be solved without guessing.