The New Sudoku Players' Forum

[groston]

I have been doing Sodukos for a while and can generally solve the ones I try. However, this one http://pairofdocs.net/wp-content/uploads/2023/03/NowWhat.jpg has me stumped. I have looked it over carefully and cannot find anything obvious that I missed. Please suggest a next step - thanks.

[Leren]

I cant get the link to work. Can anyone work it out ? Leren

[groston]

Sorry - forgot to use the URL tag stuff...

[Leren]

The link now works. Unfortunately I don't do that variant. Maybe someone else will help you. Leren

[1to9only]

what next?: Show

-2r3c78 otherwise the 2 cells will be consecutive, resulting in r34c1 being solved.
also -2r2c78. and -2r4c8. hope you make progress.

[groston]

1to9only: Thank you, you clearly see what should be done, but I am struggling with your notation. I thought that cells were identified as r#c#. So, the best that I can guess is that 2r3c78 means that the cell in row 2, column 3, which shows 2,6,7,8 should only be 7,8. But, if my understanding of your comment is correct, I don't get it...

[1to9only]

- r3c7 and r3c8 have candidates 1,2,3 - neither can be 2 as they would then be consecutive cells - so 2 can be removed from both cells (-2r3c78).
- now r3c7 and r3c8 have candidates 1,3 - 2 can be removed from r2c7, r2c8 and r4c8 for same reason as above (would result in consecutive cells).
- at this point blocks 3 and 4 can be solved.

tip for further progress: check r5c5.

when a bit stuck, i usually scan the cells with 2 and 3 candidates for (near-)consecutive candidates (123, 13, 45, etc.) and try apply the logic i've described above.
e.g. r2c6 has 1,2,3 - irrespective of the value in r2c6, 2 cannot be in r1c6 (-2r1c6). 2 can also be removed from r2c5 and r2c7 [in OP image] (-2r2c57).

later, there are a few places where this logic? (technique?) has to be used and the puzzle solves (i also required pointing and 1 naked pair).

Edit: Corrected an error in above!

[Pat]

I am struggling with your notation. I thought that cells were identified as r#c#. So, the best that I can guess is that 2r3c78 means that the cell in row 2, column 3, which shows 2,6,7,8 should only be 7,8. .

2r3c78
means
2 in row 3 columns 7,8

[1to9only]

OP image will eventually be deleted. Link to original puzzle.

Code: Select all

..................4...........8..3...........8..................
..........-......................||..-..-.........|..............|.....-............--..-.....|.|........|.|....


My notation for the layout is to describe the cell borders from top left to bottom right, | borders 2 horizontal consecutive cells, - borders 2 vertical consecutive cells.
It is clearer in expanded form:

Code: Select all

  . . . . . . .
 . . . - . . . .
  . . . . . . .
 . . . . . . . .
  . . . | | . .
 - . . - . . . .
  . . . . . | .
 . . . . . . . .
  . . . . . | .
 . . . . - . . .
  . . . . . . .
 . . - - . . - .
  . . . . | . |
 . . . . . . . .
  | . | . . . .


[groston]

1to9only: Now that I understand your notation, get what you are saying. I missed that pattern - thanks for sharing it with me.