How to make a Sudoku puzzle?

To make a Sudoku puzzle, begin with a valid completed grid, remove one clue at a time, and check after every removal that the remaining clues still allow exactly one solution. Stop when the puzzle reaches the difficulty and clue pattern you want.

Build and reduce the grid

1. Create a complete 9x9 grid that follows every row, column, and 3x3 box rule.
2. Choose a clue pattern. Many published puzzles remove cells in rotationally symmetric pairs for visual balance.
3. Remove one clue, or one symmetric pair, and test whether the puzzle still has exactly one solution.
4. Restore the clue if removing it creates multiple solutions; otherwise continue.
5. Solve the finished puzzle using human techniques to estimate its actual difficulty.

Uniqueness and difficulty are separate tests

A puzzle can have one solution and still be unpleasant or impossibly hard for its intended audience. Use the Sudoku solver to check uniqueness, then solve the grid by hand to see whether the logical path is fair. The blank grid gives you a clean worksheet for drafting clues.

SudokuPrintable.com's generator automates this process: it creates a valid solution, removes clues while rechecking uniqueness, and rejects results that miss the selected difficulty requirements.