The Ultimate FISH Guide

Advanced methods and approaches for solving Sudoku puzzles

Re: The Ultimate FISH Guide

Postby rjamil » Tue Jul 11, 2017 8:55 pm

Hi StrmCkr,

As per your pointing towards first comments:
Sherman wrote:BTW, N=2 Franken X-Wings do exist, but they are simply combinations of the basic strategies, e.g., pointing pairs and box/line reductions, so do not add anything new.

I am still not convinced that anything, which is eliminated by combination of simple strategies, will be searched by either its transposed form or combined form of advanced strategy (until or unless basic strategies omitted).

1-Fish strategy is transposed form of pointing pairs and box/line reductions strategies; and
Franken X-Wings strategy is combined form of pointing pairs and box/line reductions strategies;

Both strategies are identical and fully overlapping each other, therefore basic strategy superseded over advanced strategy.

Added on 20170712:
Many thanks StrmCkr for the clarifications in pm. I do understand that these fishes ARE really advanced strategies but certain large/complex fishes of them are also identified by more than one small/basic fishes/strategies first.

My point of view is that, "5: Pointing pairs/triplets" and "6: Box/line reduction" strategies either need to be considered as optional in order to catch complex fishes OR complex fishes do not include in program, like Andrew's solver or any other solver.

See this:
Although a "Franken" X-Wing is technically possible, but this degenerates into some other elementary single-digit technique, such as Claiming.

And this:
Illustration not available, sorry. If you have an example, I'd be grateful to you if you sent it to sudokucoach@gmail.com

By the way, adding r5c2 self cannibal candidate in following Franken X-Wings might work as well:
Code: Select all
---------+----------+----------      ---------+----------+----------
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
---------+----------+----------      ---------+----------+----------
 *  X  * |  *  *  * |  X  X  X        /  X  / |  /  /  / |  X  X  X
** *X ** |  .  .  . |  /  /  /       ** *X ** |  .  .  . |  *  *  *
 *  X  * |  *  *  * |  X  X  X        /  X  / |  /  /  / |  X  X  X
---------+----------+----------      ---------+----------+----------
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
---------+----------+----------      ---------+----------+----------
http://www.taupierbw.be/SudokuCoach/SC_FrankenXWing.shtml

R. Jamil
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Re: The Ultimate FISH Guide

Postby StrmCkr » Wed Jul 12, 2017 8:55 pm

Code: Select all
---------+----------+----------      ---------+----------+----------
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
---------+----------+----------      ---------+----------+----------
 *  X  * |  *  *  * |  X  X  X        /  X  / |  /  /  / |  X  X  X
** *X ** |  .  .  . |  /  /  /       ** *X ** |  .  .  . |  *  *  *
 *  X  * |  *  *  * |  X  X  X        /  X  / |  /  /  / |  X  X  X
---------+----------+----------      ---------+----------+----------
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
---------+----------+----------      ---------+----------+----------

the *x cell prevents the formation of the fraken X-wing => no eliminations using a 2-size fish.
the 1 size fish{cyclops} will find eliminations,
{aka box/line reduction} {aka locked Candidates}

1 in c2 => r4c13,r5c13,r6c13<>1 {left grid}

1 in b5 => r5c123789<>1 {right grid} edit: see pats note for how this works as a Mutant-fish
Last edited by StrmCkr on Mon Jul 17, 2017 11:57 am, edited 1 time in total.
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Postby Pat » Sun Jul 16, 2017 8:24 am

rjamil wrote:adding r5c2 self cannibal candidate in following Franken X-Wings might work as well:
Code: Select all
---------+----------+----------      ---------+----------+----------
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
---------+----------+----------      ---------+----------+----------
 *  X  * |  *  *  * |  X  X  X        /  X  / |  /  /  / |  X  X  X
** *X ** |  .  .  . |  /  /  /       ** *X ** |  .  .  . |  *  *  *
 *  X  * |  *  *  * |  X  X  X        /  X  / |  /  /  / |  X  X  X
---------+----------+----------      ---------+----------+----------
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
 .  /  . |  .  .  . |  .  .  .        .  *  . |  .  .  . |  .  .  .
---------+----------+----------      ---------+----------+----------

http://www.taupierbw.be/SudokuCoach/SC_FrankenXWing.shtml

on the Left -- no ( as StrmCkr has pointed out )

but on the Right -- yes this works!

    we had a 2-step approach
    ( each of them a fish of order 1 )
      b5\r5 ==> b4\c2
    but if we really wish to claim a 1-move approach
    then yes we can combine them
    ( making a fish of order 2 -- an X-wing )
    getting most of the exclusions ( except: r5c13 )
      r46\c2b6
      or
      b45\r5c2
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