Sudoku puzzle - cannot get this one out

[FenceFurniture]

I usually do at least one puzzle per day at TheSudoku.com

I have studied as many techniques as I can wrap my head around on various websites, but things like Swordfish escape me. Many times such complex explanations are very poorly written, and probably need to be one on one taught (for me anyway). The also seem to be very cutely set up to satisfy the explanation.

It has been quite some time since I haven't been able to get one solved, but this one has me stumped. I've never had to use forcing chains or XY chains before, so I read up and tried those. Nup.

If you can get this one out then can you explain how you did it?

Sudoku.jpg

If you want you can go to that site and particular puzzle by using:
https://thesudoku.com/veryhard-9603-free-sudoku

[Fekit]

There you go FF.

SD.JPG

[FenceFurniture]

Good job Feckit, but that actually tells me nowt - I can get the website to fill that it if I want.

Do I presume that you got to the same stage as I did? If so, how did you proceed from there?

[Fekit]

Yes I was at the same stage as you.

Unfortunately, as far as I can tell, it's just a long process of elimination. Personally I see them like patterns, kind of. In this particular case the 1 & the 4 were going to be the key and starting from the top right hand corner in the bottom right cell the 4 almost resolves itself without conflict the 1 worked to the left also without conflict then the 8 and the whole thing fell into place.

Apologies for that being of absolutely no strategic help whatsoever.

[FenceFurniture]

it's just a long process of elimination. Yes, but it can always be proven or deduced
starting from the top right hand corner in the bottom right cell I presume you mean r7c9
the 4 almost resolves itself without conflict ¿Que? The choices are 1247
the 1 worked to the left also without conflict then the 8 and the whole thing fell into place.

Yes I think I probably only need one more number confirmed and it will fall into place, but proving that one number is the issue.

[rustynail]

4 middle top (by process of elimination) The rest fall into place.

[FenceFurniture]

4 middle top (by process of elimination)

That's what I'm not getting Ken. You can't be talking about within that middle top 3x3 matrix, because within that all the possible combinations work (ignoring the 12 pair, and just looking at 478 48 78).

There's clearly something I'm missing here.

[dmorse]

colors. c4 and c9 each have only two cells with 7. r4c4 and r4c9 can't both be 7 so either r9c4 or r7c9 must be a 7. thus neither r7c6 nor r9c7 can be 7 and so must be 1.

[FenceFurniture]

colors. c4 and c9 each have only two cells with 7. r4c4 and r4c9 can't both be 7 so either r9c4 or r7c9 must be a 7. thus neither r7c6 nor r9c7 can be 7 and so must be 1.

Yeah! Now that makes sense but is devilish hard to see for the first time. The key seems to be looking for something that fits "c4 and c9 each have only two cells with 7." and following through from there. Does that technique have a name? (please don't say Morse Code.... )

But I don't understand what you mean by "colors".

[dmorse]

"colors" is the name of the technique. Sorry for being so terse, I hadn't finished my coffee when I posted. I'm better now!

I used the game and advice from here to practice some of the advanced solving techniques. I just checked, it still appears to work on W10.

[FenceFurniture]

All good! I'll check that out, but I've just realised your local time there. Crikey, I guess you're allowed to be terse and in need of coffee at 5.20am!

[Tonyz]

do us all a favour and go back to woodworking, its more satisfying and you learn something...sudarko ? gawd go drown your sorrows ...please

[rustynail]

Sorry mate, I mislead you. It was the 7 not the 4. I did the whole thing to the end and thought I would remember the first process of elimination. Guess too much Rugby doesnt make for good memory.

[rustynail]

do us all a favour and go back to woodworking, its more satisfying and you learn something...sudarko ? gawd go drown your sorrows ...please

Sorrow drowning never did anyone any good. Sudoku keeps the mind nimble, particularly as senility sneaks up in later years. A sharp mind never did woodworking any harm. A gut full of p.ss is catastrophic.

[FenceFurniture]

Sudoku keeps the mind nimble

Indeed, but that statement assumes the mind is nimble to begin with, eh Tonto?

For the non-Spanish speakers.