CoffeeAddict asked:


Is there a straightforward method to classify Sudoku games in terms of their complexity, whether they are easy, medium or hard (or any other scale for that matter)?

Also, is there any standardized technique or algorithm (by hand or using some open-source code) for creating Sudoku tables according to a wished level of complexity? Or is there no other way to do it than through a lot of trial and error? Also, how do you know whether you’ve stumbled upon a brand new combination? Is there a list somewhere on the Internet with tried and tested combinations?

One final question, how would you qualify this game below (and why)? Medium? Obviously, it’s not as easy as some others that I’ve tried in that it cannot be solved simply through the filled in blanks alone. But it was not extremely hard either and I can’t imagine there not being anything harder…

l _ l _ l 7 ll _ l _ l _ ll 3 l 5 l 4 l
l 8 l _ l _ ll _ l 1 l _ ll _ l _ l 9 l
l _ l 5 l _ ll _ l _ l 4 ll _ l _ l _ l

l 5 l _ l _ ll 4 l _ l _ ll 9 l _ l 8 l
l _ l 3 l _ ll 9 l 6 l _ ll 1 l _ l _ l
l 9 l _ l _ ll 5 l _ l _ ll _ l 2 l _ l

l 2 l _ l _ ll _ l 3 l _ ll 4 l 8 l _ l
l _ l _ l 3 ll _ l _ l 8 ll _ l _ l 6 l
l _ l 8 l 9 ll 2 l _ l _ ll _ l _ l _ l