Hard Sudoku
A hard sudoku keeps the ordinary rule — every digit once in each row, column and box — and simply gives you fewer starting numbers. With fewer clues, scanning stops being enough. You begin to rely on pencil marks and on patterns such as pairs, pointing digits and X-wings to decide where a number can and cannot go.
This section lists the games whose own settings go beyond medium. Each one names a hard, expert or evil level in its description, so every board here can be made genuinely demanding.
The hardest board on the site is the evil level of our Daily Sudoku. It sits above hard and expert, gives very few starting digits and usually needs advanced patterns to finish; it is the only evil-level puzzle in this section, and it changes every day. The Sudoku game with 4x4, 6x6 and 9x9 boards offers Hard and Expert, and its notes and check tools make long solves easier to manage. Sudoku Royal has four difficulties and describes its top levels as extremely challenging. Sudoku Challenge runs up to an expert mode, and Wordoku brings the same logic to letters with its own Hard level.
If a hard board stalls, the answer is rarely a guess. Our guides to sudoku techniques explain the patterns that break most expert grids. Players who want a gentler start will find it in easy sudoku.
Questions about hard sudoku
What is the difference between hard, expert and evil?
Each level removes more starting digits. Hard boards need careful pencil marks; expert and evil boards usually need advanced patterns to finish without guessing.
Which game here has an evil level?
Our Daily Sudoku. The other games in this section top out at hard, expert or their own most difficult setting.
Do hard sudokus still have one solution?
A properly built sudoku has exactly one solution at every difficulty, so logic alone is always enough.