The New Sudoku Players' Forum

[SpAce]

First, this is not meant to replace Dan's next daily puzzle (i.e. I'm hoping to see one). I'm just wondering if anyone can find a one-step solution for it because I can't. It's probably the first such puzzle I've seen in this newspaper. With two steps it's very easy (though I actually used three, my excuse being that I solved without pm and missed a basic move), but a reasonable one-stepper seems elusive. Anyone with more creativity?

Code: Select all

.1...79........63.8....2..74....8.....6.3.2.....6....97..8....6.92........34...7.

(If someone wants to solve it normally, it's a decent p&p puzzle but not much of a challenge otherwise.)

[Leren]

Best I can do is note that stte opportunities exist at 9 r2c4, 9 r3c3, 9 r4c5 & 9 r5c1.

If you first use an X Wing to remove 9 from r9c5, then they are easy to prove. If not they are problematic (for me).

Leren

[Cenoman]

Code: Select all

 +----------------------+----------------------+-----------------------+
 |  3     1      4      |  5     6      7      |  9       2     8      |
 |  259   257    579    |  19    8      149    |  6       3     145    |
 |  8     6      59     |  3    l149    2      | m145     145   7      |
 +----------------------+----------------------+-----------------------+
 |  4     357   f1579   |  2    a157-9  8      |  1357    6     135    |
 | e159   57     6      |  179   3      1459   |  2       8     145    |
 | i125   2357   8      |  6   ok1457  j145    |  13457  j145   9      |
 +----------------------+----------------------+-----------------------+
 |  7     4      15     |  8     2     n135    | m135     9     6      |
 | d156   9      2      |nb17  nb157    1356   |  8       145   1345   |
 | g156   8      3      |  4   nh159    1569   |mh15      7     2      |
 +----------------------+----------------------+-----------------------+

Three ways to present the double Kraken columns (7)r468c5 & (1)r5689c1 (computer generated solution)

"Usual" kraken writing:
Kraken column (1)r5689c1
(1-9)r5c1 = r4c3 - (9)r4c5
(1)r6c1 - (15=4)r6c68 - r6c5 = r3c5 - (415=3)r379c7 - (3=1579)b8p3458 - (9)r4c5
(1)r8c1
(1)r9c1 - (15=9)r9c57 - (9)r4c5
=> " - (1)r8c1 => - (9)r4c5"

Kraken column (7)r468c5
(7-9)r4c5
(7-4)r6c5 = r3c5 - (415=3)r379c7 - (3=1579)b8p3458 - (9)r4c5
(7)r8c5 - (7=1)r8c4 - (1)r8c1 => - (9)r4c5
=> -9 r4c5; ste
(drawback: repeted chain 4r6c5 [...] 9r4c5)

...or as a net (avoids the chain repetition):

Code: Select all

Double Kraken (7)r468c5 & (1)r5689c1
(7)r4c5*
  ||a
(7)r8c5 - (7=1)r8c4 - (1)r8c1
  ||b         c        ||d
  ||                  (1-9)r5c1 = (9)r4c3*
  ||                   ||e          f
  ||                  (1)r9c1 - (15=9)r9c57*
  ||                   ||g          h
  ||                  (1)r6c1 - (15=4)r6c68
  ||                     i          j      \
  ||                                       (4)r6c5 = r3c5 - (415=3)r379c7 - (3=1579)b8p3458*
  ||                                       /  k       l          m                 n
(7)r6c5 - - - - - - - - - - - - - - - - -   
   o
 =>-9r4c5; ste

...or as a triangular matrix (the most compact):

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9r9c5 3r7c6                                                   ALS (9157=3)b8p3458
      3r7c7 4r3c7                                             ALS (315=4)r379c7
            4r3c5 4r6c5
7r4c5             7r6c5  7r8c5
                         7r8c4 1r8c4
                  4r6c68             1r6c68                   ALS (45=1)r6c68
9r4c3                                        9r5c1
9r9c5                                              1r9c57     ALS (9=51)r9c57
                               1r8c1 1r6c1   1r5c1 1r9c1

 =>-9r4c5; ste

[SpAce]

If you first use an X Wing to remove 9 from r9c5, then they are easy to prove. If not they are problematic (for me).

Yes, that's the interesting part. Such a simple first move changes everything.

Three ways to present the double Kraken columns (7)r468c5 & (1)r5689c1 (computer generated solution)

That's awesome! Thanks, Cenoman!