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

Puzzlers ready to live dangerously and push beyond their mental comfort zone should steel themselves for the second book in the Times' toughest Killer series ye

Push your nerve and logic to the absolute limit with this third collection of The Times Killer Su Doku.