All legit sudoku puzzles have but one final solution. That's a given. However there often can be more than one way to attack a puzzle in order to reduce the possibilities down into more easily recognizable two and three number patterns. There are the rare few like the Doc who can do this without using pencil marks or "greens". The Doc is amazing. I don't know if he uses reds. Only subscribers have that option. I see you rated yesterday's a 69 Doc. I found a simple contradiction in the top three boxes and it quickly resolved from there. I had it rated in the high 20's using greens no guesses.
Jackt: My rating program rates it a 69. It is probably not very accurate in rating the experts.
I often find these puzzles were harder for me than you rated them so I guess we're even.
Difficulty score 53. No green.
crashed on me, start again
only 89 experts to go and I've caught up!
Done. NG. EZPZ.
Buggers. Some mistake.
Did it, no green. After one mistake (neither guess was right) one bad guess did it.