Super fiendish Sudoku puzzle ...

[A580Hojas]

Anyone fancy giving me a clue on this? You can see where I've put two 3s in - but now have been stumped for days!

Any suggestions very gratefully received .

@BIWI that’s exactly what I did (put all the maybes in). I’ve had a look at yours and it was exactly the same. And then I had another step where I’d eliminated some maybes based on that like @Sew3stitch means (I think).

But I couldn’t eliminate many at all and still had to use trial and error to solve it. Maybe I wasn’t looking thoroughly enough?

I don’t want to give examples of what I’m talking about until @A580Hojas‘s finished it. But when they have if anyone could use this puzzle to explain using specific examples how to go from maybes to the answer I would be really keen to learn!

There's a hidden triple in the fourth row down.

Right. So I've put all the possibles in in pencil and can't find any enlightenment anywhere.

@BIWI can you put me out of my misery? Specifically what does "there's a hidden triple in the 4th row down mean"

If you look at row four, you'll see the following possibilities (the numbers in brackets are the ones already filled in):

678 (9) 678 23568 456 34678 28 (1) 2358

The hidden triple is 678 (bolded) because those numbers can only go there

So you remove the other 6s and 8s, leaving row 4 as:

678 (9) 678 235 45 678 2 (1) 235

So now you know that you can put 2 in the 7th cell in that row
... which then means that you end up with a pair in that row: 35

... which then means that the middle cell has to be 4

So row 4 now reads:

678 (9) 678 35 (4) 678 (2) (1) 35

Does that help?

To take it a bit further, now that you have the 4, look down that column (which is the middle column) and in row 8, you have 49, so that cell has to be 9

This thread made me download a Sudoku app and lose a couple of hours last night 😑

The Guardian publishes one everyday online.

Monday is an easy one, Tuesday and Wednesday are medium and Thursday and Friday are hard. On Saturday they publish an expert one online, but also an easy and medium in the paper itself.

Part of my morning routine!

Am I missing something, @BIWI?

If the sixth box along's possibles were only 678, I'd agree with you, because then three boxes in that line could only be 6 or 7 or 8.

Or if no other box on that line could contain 6 or 7 or 8, I'd agree because they couldn't be anywhere else.

But the sixth box could also be 3 or 4 & there are other places to put the 6 & 8, if it should turn out to be 3 or 4.

Aah thanks BIWI, I'll have a go at those.

It's the combination of all three together. 678.

But no, @BIWI, because the middle one of that row is 6. (I have finished it now)

It's not a hidden triple because one of the three boxes you have bolded 678 for could also be 3 or 4 (and indeed is 4).

It's the middle column you have to look closely at - see my previous post: if you set the middle number of the top-middle box to be 6 then you get a contradiction in the middle-middle box, which means that it must therefore be 5.

This is how I've always understood the technique (will try to attach a screenshot).

Hmm. Can't seem to get MN to pick up the right screenshot. Try this link & scroll down to hidden triples.

www.angusj.com/sudoku/hints.php#:~:text

I've finished it too!

The middle number of the top middle box is 5

... but Ive just realised I have made a. mistake elsewhere

Sorry to confuse things @A580Hojas!

I had the same problem as merryhouse. I didn't find 3 boxes on the 4th row which could only be 6, 7 or 8.

Infact I didn't find any exclusive 2, 3 or even 4 combinations in any row or square. That's why I'm still stumped I suppose!

Well I've solved it now (properly - I've double checked, and it's the same solution as @Shapiro!)

I started in a different place this time. This is how I started.

In the top middle box, there are three triples - 189. That means that you take the 5 and 6 out of those cells, which means that the middle cell becomes 5 and the one to its right is 6:

189 (7) 189
(4) (5) (6)
189 (3) (2)

I can't remember where I went from there though ...

Here it is

I learnt a lot of techniques from watching these guys
m.youtube.com/c/CrackingTheCryptic
For puzzles they have solved on video over the last year or so, they give a link to an online version so that you can solve it alongside them.
And you do have to pencil mark for all but the simplest Sudokus imo.

See, my pencil marks in that top middle square are

1589, 7, 189
4, 56, 16
1689, 3, 2

And in the middle column vertically I agree with merryhouse again, the options are

7
5, 6
3
4, 5, 6
1
6, 9
8
4, 9
2

Oooooh I think I'm on the verge of giving up!

But you're right with all of those

Yes, I think my brain won't compute why all those 3 cells can only be a 1, 8 or 9. I just don't geddit .

I agree op! I'm having trouble understanding the hidden triple stuff. Take the top middle 9x9, it could be resolved using the '1' in the middle left square so how can 189 be the hidden triple? Sorry if I'm being stupid!