The Times Ultimate Killer Su Doku Book 7 (7) Paperback – October 1, 2015

The big thing I like about this whole series of killer su doku books is that the puzzles are dependably CORRECT (in addition to being very challenging and original)! In some other books, especially those delving into killer su doku, and trying to make them hard, rules are often violated (most notably the rule about duplicate digits inside a cage or the requirement of a unique solution). I've NEVER seen a rule violation in this series, and I've solved hundreds of these puzzles. Kudos!

great if you like really difficult sudoku and are good at arithmetic

Best Su Doku ever created.

Lots of killer sudoku at quite a difficult level going up to suggested time of about 2 hours 30 minutes. I can't make out the suggested times though, as it can take me the same time or longer to do the less difficult ones. The ones over 2 hours rarely take me more than 30 minutes, but occasionally I just don't get one. There's probably a strategy I haven't clicked with. I have the impression that part of the difficulty level is the ability to switch between strategies rapidly. I've never read the tips at the beginning and I think it's better in the long run as you have a better understanding when you work them out yourself - and more fun. Next level - don't fill them in, just do all of it in your head. Or get a life... just one more...

I've been doing these for years and really enjoy them- very addictive! Find the paper on this version of the book is too thin though especially if you are using a propelling pencil as it tears easily.Not bragging as I usually struggle with most books but these weren't as challenging as earlier books in the series.

I'm afraid I have to take issue with the assertion on the back cover that these are 120 of the toughest Su Doku challenges. If you are a confident Killer Su Dokuer (sad, I know) then these puzzles aren't a challenge, not even those classified as 'Extra Deadly'. I regularly do puzzles from Killer Sudoku online and their Extreme and Outrageous ones are indeed challenging. I can't even complete their Mind Bending ones. I also think that the puzzles in the Times are often more challenging than those in this book. It's handy to have a book like this to take on holiday, but I don't feel it delivers what it promises.

Book number 7 in the series. Very poor. Avoid this if you like challenging puzzles. By far the easiest in the series. Also printed on something approximating to rough toilet paper!

Love these books..very addictive. But are they as hard as they say? I can't believe my skill is increasing this much ! Keep them coming though!