The Sudoku craze continues! And now, players are ready for a real challenge. From the hardest, 300 puzzles we dare you to solve. All from the editors at Nikoli Publishing, the Japanese company that invented the game. Most Sudoku puzzles are created by computer programs, but not Nikoli's, they are written by the people who introduced the puzzle to Japan in the 1980s - and who hold the trademark for Sudoku in Japan. As Tim Preston, publishing director of Puzzler Media, Britain's biggest seller of crossword and cryptogram puzzles, has said, "It is a matter of great pride to get your puzzle into one of Nikoli's magazines. Handmade puzzles are much better...It gives you the satisfaction that you are pitting your wits against an individual who has thought about what your next step would be and has tried to obscure the path."