Play Hard Sudoku Online!

Hard sudoku is suitable for the most advanced players! The amount of empty cells to fill is 54 out of 81 cells.

Solving this sudoku requires a lot of logical reasoning, constant use of notes and familiarity with advanced techniques such as "sword fish", "hidden tripples" and others.

Why solve hard sudoku online?

The harder the sudoku, the more sense it makes to attemps solving it online compared to a pen and paper.
You have to do planty of note-taking, marks and things can get messy when doing all of that using pen and paper.
Solving a hard sudoku online is significanlty simpler and the use of the functions such as "Notes", "Undo" and "Erase" makes the challenge a lot more manageable.

Recommended time for solution?

Hard sudoku takes a lot of time to solve and can take between 17-30 minutes to reach a valid solution.

Video explaining advanced sudoku techinques