Recently, a type of sudoku called “pandigital” sudoku was featured on Passion For Puzzles. In pandigital sudoku, each of the nine rows form an equation which also provides clues for solving the puzzle.
As it turns out, the site that the puzzle was linked from includes a wealth of other sudoku variations including many mentioned here before. It’s really not worth mentioning them all here, but I’ll give a few examples to whet your appetite:
- Sudoku with unkown extra regions – Very interesting, but only one puzzle available. Essentially, you don’t know exactly where the internal squares are.
- Navigator Sudoku – Arrows in a square with a number point in a direction where that number can be found in an adjoining row or column.
- Sudoku corrections – The grid is filled out, but there are errors. Find and make corrections, but corrections can’t be made to adjoining squares.

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