The New Sudoku Players' Forum

[Pupp]

Solved my first hard puzzle! Using 10,000 Sudokus Plus (android).

The Advanced 5 could be solved with normal stuff, although somewhat tricky.

The first hard puzzle I did, I had to use X-wing on 2 different numbers (6 and 8), in order to find a hidden single, which was cell with the number 8 left as a pencil mark.

After that, the rest of the puzzle pretty much just lined up.

Considering I didn't have to use X-wing on any of the Advance 5 puzzles, I was surprised I had to solve two X-wings in order to uncover a hidden single with the very first HARD puzzle, but solving that REALLY MADE MY DAY!!!

[Pupp]

OMG!!!!!
I did a second Hard puzzle, and it was not hard at all. Not even a single triple, let alone an X-wing.

There were several doubles I needed to finess, but that's not a hard puzzle in my opinion.

I haven't come across a quad yet, but I'm under the impression, from tidbits picked up on the internet, that it's rare, unless someone hand crafts a puzzle with that.

( of course rare is relative considering there are over 6 septillion possible sudoku puzzles.

[Pupp]

So far I've solved all the hard ones I've tried. Usually I skip to the next level after a few are solved, but I think there new tricks for me to discover, so I'll stay on Hard level 1 for a while.

[Pupp]

I have a question now...

I came across this the other day, but can't remember the name of the technique. (Which I conveniently used to solve my last hard puzzle.)

You have 3 digits that repeat in 4 squares that make a box, but one of the 4 squares has an extra digit. The extra digit is the only digit that can go in that box, leaving the other 3 boxes for the 3 digits. Those 3 digits HAVE to go in those 3 boxes that are left over. It doesn't seem to be an X-Wing or an XY Wing, so I'm not sure I read about it, or just figured that out myself.

Of course, you can't solve those 3 boxes immediately, but solving the box with the extra digit was the point of the technique.

Anyway, I was wondering what that technique was called.

Oddly enough, I check the puzzle with Soduku Explainer, and it didn't mention that technique at all, so I apparently I sidestepped the easier, but longer way to solve the puzzle.

[SpAce]

Hi Pupp,

I came across this the other day, but can't remember the name of the technique. (Which I conveniently used to solve my last hard puzzle.)

You have 3 digits that repeat in 4 squares that make a box, but one of the 4 squares has an extra digit. The extra digit is the only digit that can go in that box, leaving the other 3 boxes for the 3 digits. Of course, you can't solve those 3 boxes immediately, but solving the box with the extra digit was the point of the technique.

Anyway, I was wondering what that technique was called.

I can't quite decipher your description. I guess by "square" you mean what we call a cell? What exactly do you mean by "box"'? In our parlance a box is one of the nine 3x3 areas, aka nonets or blocks.

If you provided a screenshot of the situation, I'm sure we'd know immediately what you're talking about. (Even better if you could attach a text-based grid with the pencil marks and the pattern of interest marked, like what we do in the Puzzles section. Good software solvers can export those easily.)

Oddly enough, I check the puzzle with Soduku Explainer, and it didn't mention that technique at all, so I apparently I sidestepped the easier, but longer way to solve the puzzle.

Have you tried more modern solvers, such as Hodoku, or even more modern ones like YZF_Sudoku or Sukaku Explainer? I don't have personal experience with the latter two, but based on others' experiences they seem really good. (Hodoku fulfills most of my needs quite nicely, and I'm really lazy trying out new software solvers.)

[Pupp]

Just to be clear: I SOLVED THE PUZZLE, then later put it through Sudoku Explainer, just to see it's rating mainly.

When I say square, I mean like an X-Wing thing, not a single cell, so it was 4 cells. That is, say 4/5/9 was in three of the cells, and 4/5/6/9 was in the 4th cell. So that leaves 3 cells that can only be either 4, 5, or 9. And the only cell with the 6, had to be the "6", since the other 3 numbers (4/5/9) are forced into the 3 other cells.

I was looking for quads at the time, but I notice I had these three numbers that were in 4 cells, with only a single cell containing an extra number, so I figured the extra number had to be in that cell. But what caught my eye is that the 4 cells made a box or rectangle (as oppose to a skyscraper formation).

I put the puzzle through Suduko Explainer. Apparently it finds the path that has the least difficult techniques. According to Sudoku Explainer, it's rated 2.0 (even though it was in the Hard section of my app.), but instead of what I did, it said I should have found 2x "direct hidden pairs". Not really sure I found those or not, since hidden singles and pairs is so ordinary to solve puzzles at the HARD level, that it doesn't really register as anything other than routine and expected in most of the puzzles.

In any event, after I selected the "6" for that one cell, the puzzle pretty much collapsed: singles were lining up all over the board.

I'm just trying to find the name of the technique I used.

[SpAce]

Just to be clear: I SOLVED THE PUZZLE

Perhaps, but based on your description I can't see any valid logic justifying it. Otherwise your description is still lacking crucial details to imagine the exact pattern.

When I say square, I mean like an X-Wing thing, not a single cell, so it was 4 cells.

Ok, thanks for the clarification. So you mean 4 cells in a square (or any rectangular?) shape? (That's not what you said originally. You specifically talked about 4 squares instead of 1, so it seemed like you used 'square' for a cell and 'box' for four cells in a square formation. Hence the confusion.)

That is, say 4/5/9 was in three of the cells, and 4/5/6/9 was in the 4th cell. So that leaves 3 cells that can only be either 4, 5, or 9. And the only cell with the 6, had to be the "6", since the other 3 numbers (4/5/9) are forced into the 3 other cells.

Unless all four cells were in the same house (row, column, box), I don't see any valid pattern that would let you conclude that 6 had to be in the fourth cell. If all four cells were in the same house, then it was simply a quad with one digit in a single cell (forcing it there), or more simply a triple that eliminated three digits from the fourth cell leaving there a naked single. The only way four cells can be in the same house in a rectangular formation is if they're in the same box (i.e. 3x3 block). Were they?

I was looking for quads at the time, but I notice I had these three numbers that were in 4 cells, with only a single cell containing an extra number, so I figured the extra number had to be in that cell. But what caught my eye is that the 4 cells made a box or rectangle (as oppose to a skyscraper formation).

'Rectangle' is a good, unambiguous word to describe a pattern shape. Please don't use 'box' for that purpose. In any case, like I said, I don't see a valid solving pattern based on that description, unless all four cells were in the same box.

In any event, after I selected the "6" for that one cell, the puzzle pretty much collapsed: singles were lining up all over the board.

I'm just trying to find the name of the technique I used.

"Lucky guess"?

Like I said, you should provide exact details of the pattern, preferably with an image. I don't think any of us are willing to make further guesses on what you really had based on such vague information. Questions are welcome, but you should provide enough information so they can actually be answered.

PS. The proper section for questions about solving techniques is Help with puzzles and solving techniques.

[Pupp]

It was a hidden quad essentially, but just the easiest version possible. No extra pencil marks to get rid of, and only a single box with four digits.

This is the END of the thread. I'm not going to make anymore replies for any reason whatsoever.

[tarek]

I'm not going to make anymore replies for any reason whatsoever.

Charming!

[Pupp]

I'm down to about 15 minutes per puzzle on hard 1.
I use Sudoku 10,000 Plus for new readers.

I'll do a handful more at that level, then attempt Hard 2 level.

I'd like to get below 12 minutes per puzzle before moving to the next level.

[Pupp]

I'm not sure I could get much below 13 minutes. I solved two puzzles about 15 minutes each, and I didn't spend much time looking for the lynchpin move on either puzzles. Perhaps 2 minutes. The bulk of my time is spent filling out pencil marks after I blitz through all the easy moves.

-puzzles at the level I'm on, rate between 3.0 and 3.4 on Sudoku Explainer.

[Pupp]

I decided I'm going to solve three more at my current level [Hard 1 on Sudoku 10000 Plus]. If I solve correctly without any errors, I'm going to jump to the next level.

Next level is Hard 2 on Sudoku 10000 Plus. Usually once I get past any "level 1" of a group, it goes much faster for level 2 to 5, since the puzzles are mostly designed to take more steps and just increasing the chance of a misstep, rather than technically harder. Less of the easiest steps anyway, and slowly shifts the hardest techniques closer and closer to the start of the puzzle.

[Pupp]

UPDATE.

I solved my first very hard puzzle flawlessly. (Sudoku 10000 Plus)
It consisted of using the BUG technique toward the end.

I did recognize the BUG formation (type of XY-Wing), and had to look up a tutorial on it, to finish the puzzle. Hats off to https://www.sudokuwiki.org/BUG

9...2...3
3..9.4..7
2..135..6
.9.4.8.3.
.5.....7.
.2.7.6.8.
5..341..2
7..8.9..1
1...7...8

Analysis by Sudoku Explainer

Analysis results
Difficulty rating: 4.2 (XY-Wing)
This Sudoku can be solved using the following logical methods:
47 x Hidden Single
1 x X-Wing
1 x XY-Wing
The most difficult technique (ER): XY-Wing

-------------------------------------------------------
I'm making real progress after being stuck on Hard 1 for a couple weeks, I only needed to do a couple puzzles each for levels Hard 2/3/4.

[Pupp]

I've done several " Very Hard 1" puzzles today. My favorite app is Sudoku 10000 Plus.

Puzzles are in the low 4.0 range, rated by SE.

I hit the sweet spot. Puzzles are a mix of techniques that were not in the easier "Hard" group of puzzles.
Some techniques are hard to spot, so it's really fun when I puzzle it out.

[Pupp]

I solved my first Fiendish puzzle on Sudoku 10000 Plus. Oddly enough, it was rated lower than a previous puzzle I'd done a couple days ago from the "Very Hard 5" section, and posted in a different thread on this forum.
It was rated 5.6 with a BUG technique (according to SE), somewhere in it.

I usually don't solve my problems like SE does, in all honesty. The hardest technique I used was a forcing chain.