Ultimate Sudoku Game

Ultimate Sudoku is a classic 9x9 sudoku puzzle built by Codethislab. Fill every row, column and 3x3 box with the digits 1 through 9 so no number repeats anywhere in that row, column or box — each puzzle has exactly one correct solution and can be worked out through logic alone, no guessing required.

The game keeps things simple: pick a difficulty, then work the grid one cell at a time, filling in the numbers you're certain about before tackling the trickier spots that need more elimination.

Controls

Click or tap an empty cell, then click or tap the number you want to place there. The same input works on both desktop and mobile.

Tips

• Start with the rows, columns or boxes that already have the most numbers filled in — they leave the fewest empty cells to work out.
• Look for cells where only one number can possibly fit, based on what's already in that row, column and box, before trying anything more advanced.
• If you get stuck, scan a different row or box instead of guessing — a wrong placement usually creates a conflict a few moves later.

Ultimate Sudoku offers three difficulty levels, from beginner to advanced, so it suits both a quick warm-up puzzle and a longer session for experienced solvers.