I always get stuck in a situation like, I end up guessing something and then backtracking if it turns out wrong.
Is there anything you can see?
Link: here
Reading the top line, the upper left box, upper right corner is a 2 which should open quite a few spots on the board.
And how do you get that?
I’m not an expert, but I know a website that is. Notation: top row is A1 to A9; bottom row is J1 to J9. There are a few more candidates you can eliminate from what you’ve pictured, but you’ll need to “guess” after that. (Well, more accurately, you’re looking at two possibilities at once and eliminating the one that’s contradictory. It’s easy to use a raised or lowered dot on paper next to a number, but that obviously won’t work with your average sudoku app.)
Step 1a (nested spoilers):
Look at the 8s.
Look at rows E and G.
Since either (E1 = 8 and G9 = 8) or (E9 = 8 and G1 = 8), then the other candidate 8s in columns 1 and 9 can be removed.
Step 1b:
Keep looking at the 8s.
Look at the top left 3x3 square.
Since that square must have an 8 in column 3, the 8 in cell H3 can be removed.
After that, you can guess/color. The most fruitful candidate number to color is…9…and after that, it’ll be easy.
(Like I said, I’m not an expert. This is the solution the solver I linked to gives broken up into spoilers.)
BTW, Boogly is wrong.
Thanks so much Kimble, that’s a great website!
I should have seen the “X-Wing” - I intuitively knew about them. And on a good day I might have worked out the “Pointing Pair” too. Now I have a formal understanding of these techniques.
Sorry for the delay in responding.
The top line needs to have 1-9 and the number 2 is covered in the right box leaving the only spot for that number is in the solo spot in the left box.