SudokuSolver Forum

I can't see any further moves with this puzzle. I was thinking it was invalid (multiple solutions), but Richard's SudokuSolver solved it. However, the next move it gives me is a naked double at r8c1/r5c2, which is obvious to me, but I don't see that it eliminates any candidates. Any ideas?

Never mind. Got it solved now!

Glad you got it out enzio but in case you found a different way, the way that SS uses is also valid.Both those cells are in the same nonet -> one of them must be a 6. r8c2 sees both of those cells -> no 6 in r8c2. Jigsaws offer lots of interesting eliminations I find. Enjoy them greatly.

You mentioned about uniqueness. You do have to be careful if SudokuSolver uses uniqueness to solve a puzzle. It assumes the puzzle is unique so it could actually be a false elimination. I always use JSudoku to test for a unique/valid puzzle before using SS.

Cheerio
Ed

I saw that once it was pointed out to me. For some reason, although I can spot those with vanilla 3x3 puzzles, they escape me with jigsaws.


I generally solve on paper, resorting to software only if I get hopelessly stuck. I try to choose puzzles from sources that are known to require unique solutions for their puzzles (in this case, djApe), so I figured that if in fact it did have multiple solutions, it was posted by mistake, and that the creator would want to know.