## Kraken Fish

Advanced methods and approaches for solving Sudoku puzzles
Danny, you're going to make an sd-Kraken Fish believer out of me yet.

Wintder, correct and thanks. I'll update the first post.

Also, here are a couple of multidigit Almost/Kraken Fish grouped nice loops. They where selected from Ruud's Top10000 except for the first one and AFAIC there are no equivalent grouped nice loop without fish. The thing that is common to all is the existence of multiple fins which see common nodes which is why they maintain a double implication outside of the fish. There are most likely examples which have only a single fin, but I typically only look for these guys if grouped nice loops fail so they tend to be more advanced.
Code: Select all
`Bivalued/1-element Kraken Row X-Wing (r36/c38=3, fins=r3c1|r6c3)r2c3-3- (r36)Xwing:{r3c1|r6c3=3=r3c5} -3-r1c6-8- => r2c6<>8,r1c1<>8+-----------------+-------------------+-------------------+| 13-8    7    5  | 146     2     38c |  36      9   348  ||    6    9  38bd | 147     5   37-8  |  12   1248   348  ||  138#   2    4  |  16   368*     9  |   5   1368*    7  |+-----------------+-------------------+-------------------+|    2    4    9  |   3    17     17  |   8      5     6  ||   35   15    6  |   8     4      2  | 137    137     9  ||    7   18  38#d |   5     9      6  |   4     13*    2  |+-----------------+-------------------+-------------------+|    4  568    2  |  67  3678   3578  |   9    368     1  ||   58  568    7  |   9    13  13458  | 236  23468  3458  ||    9    3    1  |   2    68    458  |  67   4678    58  |+-----------------+-------------------+-------------------+#104: 2-element Kraken Row X-Wing (r47/c19=7, fins=r47c7)r9c7=8= (r47)Xwing:{r7c7=7=r7c9|r4c79} -7-r6c59-8- r8c5=8= r8c23 -8- => r9c23<>8+---------------------+----------------------+---------------------+|     8   124    159  |     7   1245   1456  |   269  1569      3  || 12359   124      6  |   125  12345      8  |   279  1579  12579  ||  1235     7    135  |  1256      9  12356  |     4   156      8  |+---------------------+----------------------+---------------------+|  1267*    9      4  |     3    125    125  |    67#    8     57* ||   126  1268     18  | 12568      7    456  |   369  3569    459  ||   367     5    378  |    68     48b     9  |     1     2     47b |+---------------------+----------------------+---------------------+|  1579*  138      2  |  1589      6    135  | 3789#c    4    179* ||  1679  1368b   789b |     4   1238b   123  |     5  1379   1279  ||     4  13-8  159-8  | 12589   1235      7  |  2389c  139      6  |+---------------------+----------------------+---------------------+#36: 1-element Kraken Row X-Wing (r29/c56=2, fins=r2c3|r9c2)r3c5=1= (r29)Xwing:{r2c5=2=r9c2|r2c3} -2-r14678c3-1- => r3c3<>1+-------------------+--------------------+-------------------+|  468  138    134b |   456     7     9  |    2  1458   158  ||  146    5   1249# |     8  126*c  246* |  479   147     3  ||    7  128  249-1  |   245  1235c 2345  | 4589     6  1589  |+-------------------+--------------------+-------------------+|    2    4     57b |   567   568     1  |    3     9  5678  ||    3    9      8  | 24567   256  2456  |    1   257   567  ||   15    6    157b |     3     9   258  |  578  2578     4  |+-------------------+--------------------+-------------------+| 1458    7   1345b |     9  3568  3568  | 4568  1458     2  ||    9  128   1245b |   256  2568     7  | 4568     3   158  ||   58   23#     6  |     1     4    23* | 5789   578  5789  |+-------------------+--------------------+-------------------+#70: 1-element Kraken Row Swordfish (r349/c379=4, fins=r4c5|r9c6)r8c3-4- (r349)Swordfish:{r39c3=4=r4c5|r9c6} -4-r7c56-2- => r7c3|r8c6<>2+-----------------+--------------------+----------------------+|   9    2     7  |    4    35    158  |    6    138    1358  || 345  368  4568  |    7  3569   1589  |    2  13489  134589  ||   1  368  4568* |  569  2359   2589  |  345*     7   34589* |+-----------------+--------------------+----------------------+|   7   69     1  | 5689  4569#     3  |   48*   689       2  ||   2    4     3  |  689    69      7  |   18      5    1689  ||   8    5    69  |    2     1    469  |    7    349    3469  |+-----------------+--------------------+----------------------+|  45  789  89-2  |    3   246c    26c | 1458    168    1578  || 345   37    24b |    1     8  456-2  |    9     46    4567  ||   6    1   458* |   59     7    459# |  345*     2    3458* |+-----------------+--------------------+----------------------+`
Mike Barker

Posts: 458
Joined: 22 January 2006

Mike Barker wrote:Danny, you're going to make an sd-Kraken Fish believer out of me yet.

The problem I have with sd-Kraken fish is that the remote fin cells are often difficult to locate. My puzzle above shows how they can sometimes be easily located.

Take a fish where a single fin cell has already caused one or more eliminations. Mark the cells eliminated by the unfinned fish. Track all single-digit eliminations based on the premise that the fin cell is true. If the eliminations from the sd-chain include cells that you've marked, then you have a sd-Kraken fish present as well for that fin cell.
daj95376
2014 Supporter

Posts: 2624
Joined: 15 May 2006

Mike Barker wrote:Danny, you're going to make an sd-Kraken Fish believer out of me yet.

Mike, while I realize it is daj95376 originally using the sd-kraken fish term here, I distinctly recall our agreement to only apply the kraken fish term when "remote fins", or even the fish itself, were chained via link(s) of additional digit(s).

IOW sd-kraken was to be oxymoronic. If you don't support that agreement, then there wasn't any point in having made it.
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

I just reread the posts (somewhat quickly). You suggested:
Ronk wrote:Seriously, I want no part of creating another name for a fish type. I'd rather disagree forever on the definition of kraken fish -- or just call it "single-digit kraken fish."

I thought this was where we left it, but my memory isn't always spot on. What terminology do you want? As long as you're willing to keep me honest, I'll be happy to comply (except to limit Kraken fish to only single digits!)
Mike Barker

Posts: 458
Joined: 22 January 2006

Mike Barker wrote:What terminology do you want? As long as you're willing to keep me honest, I'll be happy to comply (except to limit Kraken fish to only single digits!)

To be brief ... remote-finned fish.
ronk
2012 Supporter

Posts: 4764
Joined: 02 November 2005
Location: Southeastern USA

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