Warning: Not suitable for amateur puzzlers! Prepare yourself for the toughest Su Doku challenge there is. These diabolically difficult Ultimate Killer Su Doku p
Just when you thought it was safe to pick up a pencil Killer Su Doku is based on the original Su Doku grid, with the same rules and numbers—1 to 9—but with
Perfect for coffee breaks, commutes or relaxing at home, this bumper collection of 300 brand new ultimate killer sudoku puzzles is guaranteed to provide you wit
Killer Su Doku poses an even greater challenge than the Fiendish Su Doku puzzles.Here are 100 previously unpublished puzzles for hard-core Su Doku addicts.