The New Sudoku Players' Forum

[Fortesque92]

https://ibb.co/C7tC1YQ

[Vorlauf]

There are two finned x-wings on 4s.
The first is in c57, which allows a 1 to be placed in r1c6.
The second is a sashimi finned x-wing r37, which allows a 2 to be place in r8c9

[jco]

Hi Fortesque92,

In this puzzle by inspecting the pattern for each digit, the pattern
of digit 4 satisfies Keith's trick.
For this digit you will find three single digit patterns that each
solves the puzzle (a skyscraper, a Kite, a double empty rectangle).
I have spotted also a nice W-wing (14) that solves it.
So, take a careful look at the fours.

Edit: corrected text.

[Fortesque92]

There are two finned x-wings on 4s.
The first is in c57, which allows a 1 to be placed in r1c6.
The second is a sashimi finned x-wing r37, which allows a 2 to be place in r8c9

Thank you for your response, I'm still trying to wrap my head around Finned X-Wings. Could you please tell me all the cells where the 4's for the initial Finned X-Wing are located so I can visualise the first step easier?

[yzfwsf]

Sashimi X-Wing:4r37\c57 fr3c9 => r1c7<>4
Skyscraper : 4 in r3c9,r7c7 connected by r37c5 => r1c7,r8c9 <> 4
2-String Kite: 4 in r3c5,r7c7 connected by r1c7,r3c9 => r7c5 <> 4
Dual Empty Rectangle : 4 in b2 connected by r7,c7 => r1c7,r7c5,r8c9 <> 4

[Leren]

7963...8.4286.9..35138.296...5.6..9...9.8......192..4.9872.6..513.59867.65..378.9

Code: Select all

*-----------------------------------------------*
| 7   9   6  | 3    145 14   | 125-4 8     124  |
| 4   2   8  | 6    157 9    | 157   15    3    |
| 5   1   3  | 8   b47  2    | 9     6    a47   |
|------------+---------------+------------------|
| 238 47  5  | 147  6   134  | 1237  9     1278 |
| 23  467 9  | 147  8   1345 | 12357 1235  1267 |
| 38  67  1  | 9    2   35   | 357   4     678  |
|------------+---------------+------------------|
| 9   8   7  | 2   c14  6    |d134   13    5    |
| 1   3   24 | 5    9   8    | 6     7     2-4  |
| 6   5   24 | 14   3   7    | 8     12    9    |
*-----------------------------------------------*

It's Skyscraper time again - this time on 4.

Leren

[Vorlauf]

There are two finned x-wings on 4s.
The first is in c57, which allows a 1 to be placed in r1c6.
The second is a sashimi finned x-wing r37, which allows a 2 to be place in r8c9

Thank you for your response, I'm still trying to wrap my head around Finned X-Wings. Could you please tell me all the cells where the 4's for the initial Finned X-Wing are located so I can visualise the first step easier?

Code: Select all

*-----------------------------------------------*
| 7   9   6  | 3   a145 1-4  |c1254  8     124  |
| 4   2   8  | 6    157 9    | 157   15    3    |
| 5   1   3  | 8   f47  2    | 9     6     47   |
|------------+---------------+------------------|
| 238 47  5  | 147  6   134  | 1237  9     1278 |
| 23  467 9  | 147  8   1345 | 12357 1235  1267 |
| 38  67  1  | 9    2   35   | 357   4     678  |
|------------+---------------+------------------|
| 9   8   7  | 2   b14  6    |d134   13    5    |
| 1   3   24 | 5    9   8    | 6     7     2    |
| 6   5   24 | 14   3   7    | 8     12    9    |
*-----------------------------------------------*

a,b,c,d,f denote cells of finned X-wing.
The fin is in r3c5. Candidate 4 may be removed from r1c6.

[Fortesque92]

7963...8.4286.9..35138.296...5.6..9...9.8......192..4.9872.6..513.59867.65..378.9

Code: Select all

*-----------------------------------------------*
| 7   9   6  | 3    145 14   | 125-4 8     124  |
| 4   2   8  | 6    157 9    | 157   15    3    |
| 5   1   3  | 8   b47  2    | 9     6    a47   |
|------------+---------------+------------------|
| 238 47  5  | 147  6   134  | 1237  9     1278 |
| 23  467 9  | 147  8   1345 | 12357 1235  1267 |
| 38  67  1  | 9    2   35   | 357   4     678  |
|------------+---------------+------------------|
| 9   8   7  | 2   c14  6    |d134   13    5    |
| 1   3   24 | 5    9   8    | 6     7     2-4  |
| 6   5   24 | 14   3   7    | 8     12    9    |
*-----------------------------------------------*

It's Skyscraper time again - this time on 4.

Leren

Man, spotting Skyscrapers is tough! The logic is so beautiful though. Just gotta keep practising!

[thelardoffear]

Spotting Empty Rectangles is a lot easier than Skyscrapers and usually gives the same deductions (but not in this case).

From the diagram above, the 4 in row 3 is in either position a or b.

If b (r3c5) is 4 then c (r7c5) isn't 4.
If a (r3c9) is 4 then in box 9 d (r7c7) is 4 and so c isn't 4.

So c isn't 4 and the puzzle is then solved with singles.