## [help] Give up to find some pattern?

Post the puzzle or solving technique that's causing you trouble and someone will help

### [help] Give up to find some pattern?

I have tried to find fish, xy wing, skysracper still no answer,, help please..
Danu Pr

Posts: 11
Joined: 16 February 2019

### Re: [help] Give up to find some pattern?

38..71.95.1....673..739.1.8....17834731.....9.489237.1462835917195742386873169..2

Not an easy finish but here goes.

Code: Select all
`*--------------------------------------*| 3     8  b46 | 246 7  1   |a24 9   5 || 29    1   49 | 245 58 48  | 6  7   3 ||b256  b25  7  | 3   9  46  | 1  4-2 8 ||--------------+------------+----------|| 2569  25  69 | 56  1  7   | 8  3   4 || 7     3   1  | 456 58 468 | 25 256 9 || 56    4   8  | 9   2  3   | 7  56  1 ||--------------+------------+----------|| 4     6   2  | 8   3  5   | 9  1   7 || 1     9   5  | 7   4  2   | 3  8   6 || 8     7   3  | 1   6  9   | 45 45  2 |*--------------------------------------*`

This technique is called ALS XZ Rule: X = 4, Z = 2: (2=4) r1c7 - (4=2) r1c3, r3c12; => - 2 r3c8, which solves the puzzle.

Let me explain this in words. Suppose r1c7 was not 2. Then it would be 4. Then r1c7 would be 6. So r3c12 would both be 25. In other words at least one of r1c7 and r3c12 would be 2, then r3c8 can't be 2, since it can see all three cells.

Leren
Leren

Posts: 3747
Joined: 03 June 2012

### Re: [help] Give up to find some pattern?

Probably the easiest solution:

Code: Select all
`.-----------------.-----------------.--------------.| 3     8   a4(6) | 24-6  7    1    | b24   9    5 || 29    1    49   | 245   58   48   |  6    7    3 || 25-6  25   7    | 3     9   d4(6) |  1   c24   8 |:-----------------+-----------------+--------------:| 2569  25   69   | 56    1    7    |  8    3    4 || 7     3    1    | 456   58   468  |  25   256  9 || 56    4    8    | 9     2    3    |  7    56   1 |:-----------------+-----------------+--------------:| 4     6    2    | 8     3    5    |  9    1    7 || 1     9    5    | 7     4    2    |  3    8    6 || 8     7    3    | 1     6    9    |  45   45   2 |'-----------------'-----------------'--------------'`

W-Wing:

(6=4)r1c3 - r1c7 = r3c8 - (4=6)r3c6 => -6 r1c4,r3c1; stte

SpAce

Posts: 2016
Joined: 22 May 2017

### Re: [help] Give up to find some pattern?

SpAce's W Wing is also an XY chain :

Code: Select all
`*----------------------------------------*| 3    8  a46 | 24-6 7   1   |b24  9   5 || 29   1   49 | 245  58  48  | 6   7   3 || 25-6 25  7  | 3    9  d46  | 1  c24  8 ||-------------+--------------+-----------|| 2569 25  69 | 56   1   7   | 8   3   4 || 7    3   1  | 456  58  468 | 25  256 9 || 56   4   8  | 9    2   3   | 7   56  1 ||-------------+--------------+-----------|| 4    6   2  | 8    3   5   | 9   1   7 || 1    9   5  | 7    4   2   | 3   8   6 || 8    7   3  | 1    6   9   | 45  45  2 |*----------------------------------------*`

XY Chain Length 4: (6=4) r1c3 - (4=2) r1c7 - (2=4) r3c8 - (4=6) r3c6 => - 6 r1c4; r3c1, which sloves the puzzle. You can read about XY chains here.

Leren
Leren

Posts: 3747
Joined: 03 June 2012