🧠 How to Solve a Sudoku

Sudoku is a logic-based number puzzle played on a 9×9 grid, divided into nine 3×3 subgrids. The goal is simple: fill the grid so that every row, column, and 3×3 box contains all digits from 1 through 9 exactly once. Some numbers are already given to you—these form the fixed clues that help you deduce the rest.

To start solving, look for rows, columns, or boxes that already have many numbers filled in. These are usually the easiest places to spot missing digits. For each empty cell, consider which numbers are still allowed by checking what’s already present in its row, column, and box. Often, you’ll find cells where only one number fits—these are called “singles,” and filling them in helps unlock more of the puzzle.

As you make progress, use techniques like scanning (looking across rows and columns for where a number must go), crosshatching (checking overlaps between rows and boxes), and penciling in small candidate numbers when several possibilities remain. Gradually, these candidates will narrow down as the puzzle becomes more constrained. With steady logical deduction—and no guessing required—you’ll work your way toward a fully completed and consistent grid.

🎯 Sudoku Strategy Basics

Most Sudoku puzzles can be solved using a small set of logic techniques. If you feel stuck, the goal is to eliminate candidates until a placement becomes forced.

• Look for “singles”: a cell where only one number can fit.
• Find “hidden singles”: a number that can only go in one place within a row, column, or box.
• Use pairs to eliminate candidates: if two cells share the same two candidates, those numbers are locked in.
• Watch for locked candidates in a 3×3 box that restrict where a number can appear in a row or column.

As you eliminate candidates, rescan the grid—removing one possibility often creates the next forced move.