The New Sudoku Players' Forum

[Waznboi05]

Hi everyone,

stuck now after a couple hours have to give up.

Im stuck with a bunch of 3-4 candidates and not enough 2 candidates to attempt an xy chain etc.



any help would be awesome. i dont even prefer the solution, just the technique to follow next. honestly ive probably overlooked something simple.

thanks!

[JasonLion]

I see a Sashimi Swordfish.


7.2.3..41.4.17.3.21..42.7...713.24......14.27.247...13418267.3.257943186...581274

[Leren]

The Sashimi Swordfish I saw needs to be followed by a Sashimi XWing (which is also a Skyscraper) to crack the puzzle.

An alternative is a finned Franken Jellyfish, which solves the puzzle in one move.

In all cases the fish/Skyscaper digit is 8.

Leren

[Pat]

I see a Sashimi Swordfish.

7.2.3..41.4.17.3.21..42.7...713.24......14.27.247...13418267.3.257943186...581274

Code: Select all

            /--> (8) c4\r1 -->\
(8)r5c2 -->                     --> b3 no 8
            \--> (8) r4\c9 -->/


OR as a finned fish

r4c4b3\r1c9b4 with fin at r5c4
likewise excludes (8)r5c2

[SteveG48]

Since I'm a lousy angler, I prefer multi-colors on 8's to get -8 r5c2 to reduce the puzzle to basics. There's also a kite on 8's, but it isn't needed.

[keith]

Since I'm a lousy angler, I prefer multi-colors on 8's to get -8 r5c2 to reduce the puzzle to basics. There's also a kite on 8's, but it isn't needed.

I agree. Since when did simple single-digit coloring become a Finned Franken Jellyfish?

Keith

[Leren]

Couldn't see the coloring move but did see a simple X chain : (8) r1c7 = r3c9 - r4c9 = r4c1 - r2c1 = (8) r2c6 => - 8 r1c46; stte

Leren

[keith]

After basics:

Code: Select all

+-------------------+-------------------+-------------------+
| 7     689   2     | 6-8   3     56-89 | 5689a 4     1     |
| 5689e 4     569   | 1     7     5689f | 3     569   2     |
| 1     3689  3569  | 4     2     5689  | 7     569   589b  |
+-------------------+-------------------+-------------------+
| 5689d 7     1     | 3     59    2     | 4     569   589c  |
| 35689 3689  3569  | 68    1     4     | 5689  2     7     |
| 5689  2     4     | 7     59    68    | 5689  1     3     |
+-------------------+-------------------+-------------------+
| 4     1     8     | 2     6     7     | 59    3     59    |
| 2     5     7     | 9     4     3     | 1     8     6     |
| 369   369   369   | 5     8     1     | 2     7     4     |
+-------------------+-------------------+-------------------+

a and f are pincers on 8. I call this single-digit coloring: You may have a different name.

Keith

[Leren]

keith wrote : a and f are pincers on 8. I call this single-digit coloring: You may have a different name.

Actually your move is the same as my X chain but I would not call it single-digit coloring, because there is no Strong link between the 8's in cells d and e. Thus they are not conjugates and can't, in general, take opposite colors.

This point is made clear, for example, here and here.

Not only that, cells a and f appear to take on different colors in the X chain, but that only proves that they both can't be False, not that one is True and one is False.

As it turns out they are both True in the solution, so they are not conjugates !

Leren

[SteveG48]

Couldn't see the coloring move but did see a simple X chain : (8) r1c7 = r3c9 - r4c9 = r4c1 - r2c1 = (8) r2c6 => - 8 r1c46; stte

Leren

8r1c4 = 8r5c4
8r1c7 = r3c9 - r4c9 =8r4c1

[Leren]

Couldn't see the coloring move but did see a simple X chain : (8) r1c7 = r3c9 - r4c9 = r4c1 - r2c1 = (8) r2c6 => - 8 r1c46; stte

Leren

8r1c4 = 8r5c4
8r1c7 = r3c9 - r4c9 =8r4c1

8r2c1 = 8r2c6
8r4c1 = r4c9 - r3c9 = 8r1c7

Leren

[keith]

keith wrote : a and f are pincers on 8. I call this single-digit coloring: You may have a different name.

Actually your move is the same as my X chain but I would not call it single-digit coloring, because there is no Strong link between the 8's in cells d and e. Thus they are not conjugates and can't, in general, take opposite colors.

This point is made clear, for example, here and here.

Not only that, cells a and f appear to take on different colors in the X chain, but that only proves that they both can't be False, not that one is True and one is False.

As it turns out they are both True in the solution, so they are not conjugates !

Leren

Leren,

I did not say they are conjugates, I said they are pincers. This is the same logic as a (Turbot) kite or skyscraper: One or both of the base cells are false, one or both of the pincers are true.

Over the years I have become quite adept at finding these things without having to draw anything but rudimentary diagrams in some cases. I do not use software, I solve puzzles in my armchair using pencil and paper. (I do use software to check my work and do the formatting for discussion forums like this one.)

Keith