I think I'm stuck. What tool , method do I need to move on.

[lthaus]

I'm working my way on Level 4 and trying to not just spam wrong numbers. I think I have used the proper notation and I'm just to a point where I keep staring at it and can't see the next move. Screeeshot posted in ScreenShots. Not sure how to add it here.

[OrpheusTheBard]

I think you used the right notation but maybe did just a single pass on all the numbers? I usually do two or three passes because numbers you fill in will unlock more possibilities.

Look again at the 4 and 9 on box 1 and how it affects box 7.

You will also need to be familiar with how pairs work, and the concept of a row/column "pointing" at something (both of which you'll see used on most of the YouTube channel videos so just watch a few).

I also found (and still find) this site invaluable when I was learning the ropes, for the times when I really hit a wall and had absolutely no idea what to do after hours: https://www.sudokuwiki.org/sudoku.htm

I learnt most of the techniques by necessity that way, by trying, failing, checking what I was missing with the Solver, and learning from my mistakes.

But Classic Sudoku has a built-in Hint system (with IMO very well written and useful hints) so you can check that too.

[lthaus]

Thank you! I will check out the link. I was holding off on the hint till my head hurt. BUT I did notice another couple numbers as you described them. I'm up over 60 min on this one with first 2 hints down.

[OrpheusTheBard]

By the way, the Snyder notation you're using is also how I first learnt how to solve Sudoku, and it worked very well on all easy and medium puzzles. But once I got to hard puzzles I started getting stuck almost every time...

Simon makes it look easy and you'll often see him spotting hidden singles, pairs, triples, Y-wings, swordfishes, all kinds of patterns, while still using Snyder notation, which I find really impressive.

But for me, most of the time I need to use full notation to be able to notice the advanced stuff.

Now what I do is use Snyder notation for phase one, get most of the easy numbers filled in, and then switch to full notation after I get really stuck (full means that I fill in all possibilities for every cell in the grid).

Sometimes I do it in three phases, first Snyder with pairs, then Snyder with triples (which can reveal some x-wings and pointing triples I was missing), and finally full notation.

[lthaus]

After keying that puz into the solver.. and it showing me full notation, I think I will start doing that from now on. Makes sense.

[OrpheusTheBard]

The solver does use full notation, but I was talking about puzzles much harder than this one. For puzzles like this where you can solve from start to end with just hidden singles, naked pairs and pointing pairs, I recommend sticking with Snyder notation all the way through. Switch to full only when you've tried everything you can possibly think of and have run out of options.

[lthaus]

I understand. normal first till stuck then fill in all notes. that level 4 took me 123:13 Thank you for the direction.

[lthaus]

so, again Thank you.. Puz 5 went down in 14:15 with no hints I'll do a few more and go back to redo 4 and see if I get jammed up.