## 25 oktober

Post puzzles for others to solve here.

### 25 oktober

Other strategies possible than simple colouring on 4's?
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Sudoku123456789

Posts: 34
Joined: 10 September 2017

### Re: 25 oktober

The puzzle solved cell status in line format : 7.63.9158..58716.9891.5637...87.4.1..791.258.1.25.8.37.13..7865.87.15..3..4.83791

Would you believe that this puzzle solves with ..... a Skyscraper in cells a-b-c-d !

Code: Select all
`*------------------------------------*| 7   24  6 | 3   24  9 | 1  5    8  ||a234 234 5 | 8   7   1 | 6  2-4  9  || 8   9   1 | 24  5   6 | 3  7   d24 ||-----------+-----------+------------|| 356 356 8 | 7   369 4 | 29 1    26 ||b346 7   9 | 1   36  2 | 5  8   c46 || 1   46  2 | 5   69  8 | 49 3    7  ||-----------+-----------+------------|| 29  1   3 | 249 24  7 | 8  6    5  || 69  8   7 | 69  1   5 | 24 24   3  || 256 256 4 | 26  8   3 | 7  9    1  |*------------------------------------*`

or alternatively an X Chain or Empty Rectangle move in cells a-b-c-d

Code: Select all
`*-------------------------------------*| 7    24  6 | 3   24  9 | 1   5   8  || 23-4 234 5 | 8   7   1 | 6  d24  9  || 8    9   1 | 24  5   6 | 3   7  c24 ||------------+-----------+------------|| 356  356 8 | 7   369 4 | 29  1   26 ||a346  7   9 | 1   36  2 | 5   8  b46 || 1    46  2 | 5   69  8 | 49  3   7  ||------------+-----------+------------|| 29   1   3 | 249 24  7 | 8   6   5  || 69   8   7 | 69  1   5 | 24  24  3  || 256  256 4 | 26  8   3 | 7   9   1  |*-------------------------------------*`

Leren
Leren

Posts: 3323
Joined: 03 June 2012

### Re: 25 oktober

Dear Leren, I would not believe (I missed it again)! Haha
Sudoku123456789

Posts: 34
Joined: 10 September 2017

### Re: 25 oktober

I found the the same ER can lead to -4R5C9
Sudoku123456789

Posts: 34
Joined: 10 September 2017

### Re: 25 oktober

Sudoku123456789 wrote:I found the the same ER can lead to -4R5C9

Can't see it myself unless you are referring to a different ER. The only other cell that cells a & d can both see is r5c8, which doesn't have a 4.

Leren
Leren

Posts: 3323
Joined: 03 June 2012

### Re: 25 oktober

It is actually the same ER, but the other way around (ERI = R2C9, strong link 4 R2C1 = R2C5) -->) -R4C9

Side question: how do I note a strong link on a single digit in the same row/collum?
Sudoku123456789

Posts: 34
Joined: 10 September 2017

### Re: 25 oktober

Sudoku123456789 wrote:It is actually the same ER, but the other way around (ERI = R2C9, strong link 4 R2C1 = R2C5) -->) -R4C9

Side question: how do I note a strong link on a single digit in the same row/collum?

OK I see it now but the elimination is - 4 r5c9 and there is a column Strong link (4) r2c1 = (4) r5c1.

In Eureka notation Strong links are usually denoted by an equal sign and (for brevity) you don't have to repeat a digit in the middle of a chain unless it changes.

You could have written this as an X chain : (4) r3c9 = r2c8 - r2c1 = (4) r5c1 => - 4 r5c9

Leren
Last edited by Leren on Tue Oct 31, 2017 6:50 pm, edited 1 time in total.
Leren

Posts: 3323
Joined: 03 June 2012

### Re: 25 oktober

Leren wrote:
Sudoku123456789 wrote:It is actually the same ER, but the other way around (ERI = R2C9, strong link 4 R2C1 = R2C5) -->) -R4C9

Side question: how do I note a strong link on a single digit in the same row/collum?

OK I see it now but the elimination is - 4 r5c9 and there is a column Strong link (4) r2c1 = (4) r5c1.

In Eureka notation Strong links are usually denoted by an equal sign and (for brevity) you don't have to repeat a digit in the middle of a chain unless it changes.

You could have written this as an X chain : (4) r3c9 = r2c8 - r2c1 = (4) r5c5 => - 4 r5c9

Leren

(4) r3c9 = r2c8 - r2c1 = (4) r5c1 => - 4 r5c9

I guess we're both human
Sudoku123456789

Posts: 34
Joined: 10 September 2017

### Re: 25 oktober

Sudoku123456789 wrote : (4) r3c9 = r2c8 - r2c1 = (4) r5c1 => - 4 r5c9 I guess we're both human

Hopefully True Fixed. leren
Leren

Posts: 3323
Joined: 03 June 2012