9:26 am
drwho
JudyHall, I'm flattered that you think my web page about Sudoku is fantastic and I'm happy that you are finding it helpful. Since you are reading it and since TallMike has given a good summary of how the auto-green script works, I will only add one more comment on that. The auto-green script only does the first stage of the first technique (missing digit scan) that I describe on my website.
On a slightly different subject, which I have commented on here before: The techniques I have identified at my website can be used to classify the puzzles here, or vice versa. If a puzzle here is marked easy, then I have found that only the first 2 techniques (missing digit scan and crosshatching) are necessary to solve that puzzle. If the puzzle is marked medium then the additional technique of virtual crosshatching is required (credit to UnikeTheHunter for naming that technique). If a puzzle is marked hard then the techniques of tuples analysis are required. Expert puzzles require other techniques of which I only explain one at my website since I have found it to be sufficient for solving any expert puzzle I have encountered so far.
9:48 am
drwho
Difficulty 25. After my comment on the relation of the easy, medium, hard and expert classifications to solution techniques, I used a hard technique to solve this one. However, my rating software assures me that was unnecessary.
12:17 pm
KnightTime
so to back up drwho's analysis - I was able to solve with only missing digit, crosshatching, and virtual crosshatching. However, unlike drwho, I have to reach into all my bag of tricks to solve some experts. Plus I find online sudoku more challenging that paper sudoku regardless of rating. I think the vertical orientation is the source of the problem.
2:15 pm
UnikeTheHunter
No problemo. Several pairs. One unusual virtual. But I breezed through them. 16.
5:06 pm
zoomzoom
tuples analysis? Never heard of it.
