Fiendish Sudoku

 

Over the last two or three years, I have made my way from simple Su Doku puzzles to increasingly difficult ones. The "Puzzler" and "The Big Su Doku Puzzle Magazine" each have three levels of difficulty: easy, medium and tricky. However, I have now graduated to the last of these through the "The Times Fiendish Su Doku" books. Here they describe this level as follows:

This is the premiership level of Su Doku, because Fiendish puzzles are the ones used in The Times National Su Doku Championship and World Su Doku Championship. You can find harder puzzles ...... but Fiendish are the hardest that can be solved in a reasonable time without any element of luck.

Those harder puzzles, or Super Fiendish, are at the back of the book, but require what is called a trial path. The book calls it "the elephant in the room" as it is described as "controversial because some people refuse to use it on the basis that it is guessing". I'm going to stick with the Fiendish puzzles. I'm not very fast, but faster than I used to be.