The New Sudoku Players' Forum

[daj95376]

Code: Select all

 +-----------------------+
 | 1 . 4 | . . . | . . 6 |
 | . 5 8 | 1 . . | . 2 . |
 | 6 3 2 | 8 . 4 | . . . |
 |-------+-------+-------|
 | . 4 3 | . . 8 | . . . |
 | . . . | . 1 . | . . 2 |
 | . . 6 | 4 . 5 | . . . |
 |-------+-------+-------|
 | . . . | . . . | 6 . 1 |
 | . 8 . | . . . | . 3 7 |
 | 3 . . | . 8 . | 2 5 . |
 +-----------------------+


Play this puzzle online at the Daily Sudoku site

[pjb]

Following basics, a sequence of Sashimi X-Wings (skyscrapers if you prefer):

Sashimi X-Wing of 7s at r15c2, r16c8
7s at r6c7 and r6c8 only ones in box.
Sashimi X-Wing of 9s at r15c2, r16c8
Sashimi X-Wing of 9s at r3c59, r6c58 => stte

Phil

[Marty R.]

Code: Select all

+-------------+-----------------+-----------+
| 1    79 4   | 235  235   23   | 8   79 6  |
| 79   5  8   | 1    679   679  | 4   2  3  |
| 6    3  2   | 8    79    4    | 57  1  59 |
+-------------+-----------------+-----------+
| 2579 4  3   | 279  279   8    | 1   6  59 |
| 8    79 579 | 3679 1     3679 | 357 4  2  |
| 279  1  6   | 4    2379  5    | 37  79 8  |
+-------------+-----------------+-----------+
| 4579 2  579 | 3579 34579 379  | 6   8  1  |
| 45   8  15  | 256  2456  126  | 9   3  7  |
| 3    6  179 | 79   8     179  | 2   5  4  |
+-------------+-----------------+-----------+


Play this puzzle online at the Daily Sudoku site

Remote Pairs (79) plus a transport.

79r2c1-r2c56=r3c5-r3c79=r1c8-r6c8=>r6c15<>79

[ArkieTech]

Remote Pairs (79) plus a transport.

Nice find!

[daj95376]

Any of several finned Franken Swordfish will crack this puzzle, but you can also use a simple X-network as well.

Code: Select all

 +-----------------------------------------------------------------------+
 |  1     a79     4      |  235    235    23     |  8      79     6      |
 | b79     5      8      |  1     c679   c679    |  4      2      3      |
 |  6      3      2      |  8     d79     4      |  57     1      59     |
 |-----------------------+-----------------------+-----------------------|
 |  2579   4      3      |  279    279    8      |  1      6      59     |
 |  8      79     579    |  3679   1      3679   |  357    4      2      |
 | e279    1      6      |  4     e2379   5      |  37    f79     8      |
 |-----------------------+-----------------------+-----------------------|
 |  4579   2      579    |  3579   34579  379    |  6      8      1      |
 |  45     8      15     |  256    2456   126    |  9      3      7      |
 |  3      6      179    |  79     8      179    |  2      5      4      |
 +-----------------------------------------------------------------------+
 # 69 eliminations remain

 (9):  r1c2 = r2c1* - r2c56 = r3c5 - *r6c15 = r6c8  =>  r1c8<>9


What I find interesting about this pattern is that it would be a simple odd-agon if r6c5 did not contain <9>. However, even with r6c5 containing <9>, it can be viewed as a Kraken odd-agon because we have:

(9): r6c5 - r23c5 = r2c6 - r2c1 = r1c2 => r1c8<>9.

[daj95376]

Code: Select all

+-------------+-----------------+-----------+
| 1    79 4   | 235  235   23   | 8   79 6  |
| 79   5  8   | 1    679   679  | 4   2  3  |
| 6    3  2   | 8    79    4    | 57  1  59 |
+-------------+-----------------+-----------+
| 2579 4  3   | 279  279   8    | 1   6  59 |
| 8    79 579 | 3679 1     3679 | 357 4  2  |
| 279  1  6   | 4    2379  5    | 37  79 8  |
+-------------+-----------------+-----------+
| 4579 2  579 | 3579 34579 379  | 6   8  1  |
| 45   8  15  | 256  2456  126  | 9   3  7  |
| 3    6  179 | 79   8     179  | 2   5  4  |
+-------------+-----------------+-----------+


79r2c1-r2c56=r3c5-r3c79=r1c8-r6c8=>r6c15<>79

Your notation starts with a weak inference (-), and that appears to have led you astray. If you start with a strong inference, then you'll only get r6c1<>79 -- which is insufficient to crack the puzzle.

Code: Select all

(79):  r2c1 = r2c56 - r3c5 = r3c7|r3c9 - r1c8 = r6c8  =>  r6c1<>79


Similar results -- plus an elimination in r5c7 -- can be obtained using the Skyscraper pattern a-b-c-d for the cells of the Remote Pair.

Code: Select all

 +-----------------------------------------------------------------------+
 |  1     b79     4      |  235    235    23     |  8     c79     6      |
 |  79     5      8      |  1      679    679    |  4      2      3      |
 |  6      3      2      |  8      79     4      |  57     1      59     |
 |-----------------------+-----------------------+-----------------------|
 |  2579   4      3      |  279    279    8      |  1      6      59     |
 |  8     a79     579    |  3679   1      3679   |  35-7   4      2      |
 |  2-79   1      6      |  4      2379   5      |  37    d79     8      |
 |-----------------------+-----------------------+-----------------------|
 |  4579   2      579    |  3579   34579  379    |  6      8      1      |
 |  45     8      15     |  256    2456   126    |  9      3      7      |
 |  3      6      179    |  79     8      179    |  2      5      4      |
 +-----------------------------------------------------------------------+
 # 69 eliminations remain


[Marty R.]

Your notation starts with a weak inference (-), and that appears to have led you astray. If you start with a strong inference, then you'll only get r6c1<>79 -- which is insufficient to crack the puzzle.

Danny, I'm not sure exactly what you're saying, if my solution is wrong or notation is wrong or both. Based on what I think I've learned, ABCD is a valid Remote Pairs. Then I transported A to F via E.

Code: Select all

+---------------+--------------------+-------------+
|  1     79 4   | 235   235     23   | 8   C79  6  |
| F79    5  8   | 1    E679    E679  | 4    2   3  |
|  6     3  2   | 8    A79      4    | 57   1  B59 |
+---------------+--------------------+-------------+
|  2579  4  3   | 279   279     8    | 1    6   59 |
|  8     79 579 | 3679  1       3679 | 357  4   2  |
|  2-7-9 1  6   | 4     23-7-9  5    | 37  D79  8  |
+---------------+--------------------+-------------+
|  4579  2  579 | 3579  34579   379  | 6    8   1  |
|  45    8  15  | 256   2456    126  | 9    3   7  |
|  3     6  179 | 79    8       179  | 2    5   4  |
+---------------+--------------------+-------------+

[Ngisa]

Remote Pairs (79) plus a transport.

Nice find!

[JC Van Hay]

Remote Pairs (79) plus a transport.

79r2c1-r2c56=r3c5-r3c79=r1c8-r6c8=>r6c15<>79

One should read instead : 79r2c1=r2c56-r3c5=r3c79-r1c8=r6c8=>r6c15<>79
Another presentation : On 7s and 9s : Kite(C8R3)-r2c56=r2c1 :=> r6c51<>79

[Marty R.]

Remote Pairs (79) plus a transport.

79r2c1-r2c56=r3c5-r3c79=r1c8-r6c8=>r6c15<>79

One should read instead : 79r2c1=r2c56-r3c5=r3c79-r1c8=r6c8=>r6c15<>79
Another presentation : On 7s and 9s : Kite(C8R3)-r2c56=r2c1 :=> r6c51<>79

JC, I understand your notation, but I don't understand what's wrong with my original. I know I've read that the first inference should be strong, and I accept it, but looking at my original I just can't see what about it doesn't work. The start and end cells have opposite polarity and I can't see the flaw.

[JC Van Hay]

Remote Pairs (79) plus a transport.

79r2c1-r2c56=r3c5-r3c79=r1c8-r6c8=>r6c15<>79

One should read instead : 79r2c1=r2c56-r3c5=r3c79-r1c8=r6c8=>r6c15<>79
Another presentation : On 7s and 9s : Kite(C8R3)-r2c56=r2c1 :=> r6c51<>79

JC, I understand your notation, but I don't understand what's wrong with my original. I know I've read that the first inference should be strong, and I accept it, but looking at my original I just can't see what about it doesn't work. The start and end cells have opposite polarity and I can't see the flaw.

But what does "opposite polarity" mean One true and one false ...
Hope the following will make it clearer for you.
If the first and the last inferences in a chain are

• weak, then "start" and "end" can be false, but not true together (the chain can be read : if "start" is true, then ... "end" is false -> at most one is true) :=> elimination of "start" and "end" if they are identical.
• strong, then "start" and "end" can be true, but not false together (the chain can be read : if "start" is false, then ... "end" is true -> at least one is true) :=> elimination of any candidate seeing "start" and "end".

[daj95376]

Okay Marty. Let's take one thing at a time ... starting with your Remote Pair on <79>. Cell "B" contains <59> and can't be part of a Remote Pair on <79>. Since your original chain contained r3c79, I assumed that you were transporting <7> through r3c7 and that you were transporting <9> through r3c9.

Code: Select all

 +-----------------------------------------------------------------------+
 |  1      79     4      |  235    235    23     |  8     C79     6      |
 |  79     5      8      |  1      679    679    |  4      2      3      |
 |  6      3      2      |  8     A79     4      | b57     1     B59     |
 |-----------------------+-----------------------+-----------------------|
 |  2579   4      3      |  279    279    8      |  1      6      59     |
 |  8      79     579    |  3679   1      3679   |  357    4      2      |
 |  279    1      6      |  4      2379   5      |  37    D79     8      |
 |-----------------------+-----------------------+-----------------------|
 |  4579   2      579    |  3579   34579  379    |  6      8      1      |
 |  45     8      15     |  256    2456   126    |  9      3      7      |
 |  3      6      179    |  79     8      179    |  2      5      4      |
 +-----------------------------------------------------------------------+
 # 69 eliminations remain


As for notation, your =/- usage was in error; i.e., reversed. This caused me to miss how r6c5<>79 could occur. Also, when you talk about a structure and a transport, it'd be easier on the rest of us if you wrote the structure at the start of the chain and the transport at the end (whenever possible). Example:

Code: Select all

(79):  [ r6c8 = r1c8 - r3c79 = r3c5 ] - r2c56 = r2c1  =>  r6c15<>79


[Leren]

Code: Select all

*--------------------------------------------------------------*
| 1    c79    4      | 235   235   23     | 8    b79    6      |
|e79    5     8      | 1    f679  f679    | 4     2     3      |
| 6     3     2      | 8    g79    4      | 57    1     59     |
|--------------------+--------------------+--------------------|
| 2579  4     3      | 279   279   8      | 1     6     59     |
| 8    d79    579    | 3679  1     3679   | 35-7  4     2      |
| 2-79  1     6      | 4     23-79 5      | 37   a79    8      |
|--------------------+--------------------+--------------------|
| 4579  2     579    | 3579  34579 379    | 6     8     1      |
| 45    8     15     | 256   2456  126    | 9     3     7      |
| 3     6     179    | 79    8     179    | 2     5     4      |
*--------------------------------------------------------------*

The way I see Marty's move is:

Code: Select all

(79): r6c8 = r1c8 - r1c2 = r5c2                => -79 r6c1, -7 r5c7
                     ||
                         = r2c1 - r2c56 = r3c5 => -79 r6c5

Leren

[Marty R.]

Cell "B" contains <59> and can't be part of a Remote Pair on <79>.

Danny, this is something that I learned from Keith, if I interpreted correctly. This can be Remote Pairs as long as there's a strong link: AB-AB-AC-AB.

http://www.dailysudoku.co.uk/sudoku/for ... =9089#9089

it'd be easier on the rest of us if you wrote the structure at the start of the chain and the transport at the end (whenever possible).

I don't doubt that at all, but sometimes I just can't figure out how to do it because the notation doesn't flow like my solution did. Sort of like an XY-Wing. I see the pivot and each branch but it's notated as an XY-Chain.

[daj95376]

http://www.dailysudoku.co.uk/sudoku/for ... =9089#9089

Your link is broken and I can't check your reference.