## Double swordfish?

Advanced methods and approaches for solving Sudoku puzzles
ronk wrote:
CathyW wrote:1st swordfish found at this point:
................
And after the eliminations from that you get a second swordfish as follows:

I find it amazing that the 2 swordfish exist simultaneously! The first(*) in rows 2, 6, and 9 ... the second(+) in columns 2, 5, and 9.
Code: Select all
` 9     +1246   12467  | 1268  +167    2678   | 5      3     +12   8      5     *1267   | 4      3      267    |*12     67     9    126    3      1267   | 1269   5      2679   | 8      67     4   ----------------------+----------------------+------------------- 5     +1467   9      | 16     8      3      | 1467   2     +17   1246  +12467  3      | 1256  +146    2456   | 9      458   +178 *1246   8     *1246   | 7      9      2456   |*146    45     3   ----------------------+----------------------+------------------- 7      46     8      | 369    2      469    | 34     1      5    3      246    2456   | 568    467    1      | 247    9      278 *124    9     *1245   | 358    47     4578   | 2347   48     6   `

This might not be unusual. See here.
tso

Posts: 798
Joined: 22 June 2005

tso wrote:
ronk wrote:
CathyW wrote:1st swordfish found at this point:
................
And after the eliminations from that you get a second swordfish as follows:

I find it amazing that the 2 swordfish exist simultaneously!

This might not be unusual. See here.

Your are correct. On the Swordfish, Slot Machines and Pomeranians thread ...
Myth Jellies wrote:Every NxN swordfish in rows/columns has a mirror MxM swordfish in colums/rows, where M + N = 9 - number of solved cells for the digit in question.

... and I believe anyone that can come up with a formula. BTW that's not an exact quote as I added the " + N".
ronk
2012 Supporter

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

Code: Select all
`  9     +1246   12467  | 1268  +167    2678   |  5      3     +12   #8      5    #*1267   |#4      3      267    |#*12     67     9     #126    3     #1267   |#1269   5      2679   | #8      67     4    -----------------------+----------------------+--------------------   5     +1467   9      | 16     8      3      |  1467   2     +17    1246  +12467  3      | 1256  +146    2456   |  9      458   +178 #*1246   8    #*1246   |#7      9      2456   |#*146    45     3    -----------------------+----------------------+--------------------   7      46     8      | 369    2      469    |  34     1      5      3      246    2456   | 568    467    1      |  247    9      278 #*124    9    #*1245   |#358    47     4578   | #2347   48     6   `

I think the aforementioned starred 3x3 swordfish is actually a degenerate piece of the hashed 4x4 jellyfish. The 3x3 swordfish marked with '+'s is the mirror to the hashed jellyfish, and it satisfies the N + M = 9 - number of solved cells rule.
Myth Jellies

Posts: 593
Joined: 19 September 2005

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