Microsoft Sudoku

Enjoy free online sudoku puzzles and enhance your logical thinking skills. This engaging brain-teaser from Microsoft offers two exciting game modes. The classic sudoku consists of 9x9 grids divided into standard 3x3 regions. Each level provides only 3 hints, but you're encouraged to jot down notes to help solve the sudoku puzzles online for free. Additionally, you can highlight incorrect numbers to avoid duplicates while you play. 

In addition to the traditional sudoku game, there are also irregular levels with 4 different difficulty settings. The requirement for numbers remains the same: they must be unique in every row, column, and region. However, these regions feature random, non-square borders. I believe all fans of free board games will enjoy this captivating puzzle experience.