Sudoku
Classic number logic, no guessing
Sudoku is a logic puzzle played on a 9×9 grid split into nine 3×3 boxes. Fill every empty cell with digits 1-9 so each row, column, and box contains each digit exactly once.
Rules
Each empty cell must contain exactly one digit from 1 through 9.
Every row must contain all digits 1-9 with no duplicates.
Every column must also contain all digits 1-9 with no duplicates.
Each 3×3 box must contain digits 1-9 exactly once.
Strategies & Tips
Scan Singles First
Start with rows, columns, or boxes that already contain many numbers. Fewer missing digits means easier placements.
Use Pencil-Mindset Candidates
For each empty cell, mentally test which numbers are blocked by row, column, and box. If only one candidate remains, place it.
Cross-Hatch Boxes
When a number is constrained within a box, use row/column eliminations to locate its exact cell.
Spot Naked and Hidden Singles
A naked single is a cell with only one possible digit left. A hidden single is a digit with only one possible cell left in a row, column, or box. Scanning for both is the fastest route through easy and medium puzzles.
Avoid Guessing
Daily Sudoku puzzles are designed to be solved with logic. If stuck, move to another region and gather more constraints.