BUG+1 didn’t work? And question about spotting naked singles
Hi! I’ve always enjoyed Sudoku but only today have I started looking into solving techniques rather than just guessing my way to the end. It all made sense until I tried to apply it.
I just read a bit about the BUG+1 technique which seems like the trick to apply for the case I was left with in the first picture (ignore the highlighted 3’s, I forgot to turn it off). If I understood that technique correctly, the solution to the box with the three values in it (selected in the photo) would have been 6, since 6 appears three times in the box unlike any of the other digits. But this is incorrect. In the third photo the hint told me the answer is 7 due to “Naked Single.” What am I missing there?
Also, it seems as though “Naked Singles” are pretty obvious. But the hints given in image 2 and 3 “explain” the corresponding answers as a naked single, and yet I don’t see how I could have been certain that the digit didn’t belong in the other box in the row/column since I was left with so many pairs. Is there a better explanation for either of those?
Thanks for helping me understand and get better!
(ETA: I just realized I forgot I was playing odd/even sudoku! So I guess I should have known the 3 went in the top right corner. But still would like to see how you explain the answers to my questions for learning purposes!)