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ZeroAssoluto
Joined: 05 Feb 2017
Posts: 942
Location: Rimini, Italy
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 Posted: Fri Sep 17, 2021 8:12 am Post subject: Sep 17 VH |
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Hi everyone
| Code: |
+----------------+--------------+------------+
| 23689 269 389 | 4 7 25 | 18 158 19 |
| 4 29 89 | 1 25 3 | 6 578 79 |
| 1 7 5 | 9 6 8 | 3 4 2 |
+----------------+--------------+------------+
| 289 1 489 | 5 234 24 | 7 68 36 |
| 5 3 6 | 78 19 79 | 18 2 4 |
| 28 24 7 | 38 1234 6 | 5 9 13 |
+----------------+--------------+------------+
| 7 8 2 | 6 49 1 | 49 3 5 |
| 369 4569 1 | 2 3459 4579 | 49 67 8 |
| 369 4569 349 | 37 8 4579 | 2 167 167 |
+----------------+--------------+------------+
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Play this puzzle online at the Daily Sudoku site
XY-Wing 1,3,8 in r5c7,r6c49 and -8 in r5c4
Ciao Gianni |
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TomC
Joined: 30 Oct 2020
Posts: 358
Location: Wales
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| Posted: Sat Sep 18, 2021 6:08 am Post subject: |
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| Code: |
+------------------+----------------+------------+
| 23689 269 389 | 4 7 25 | 18 158 19 |
| 4 29 89 | 1 25 3 | 6 578 79 |
| 1 7 5 | 9 6 8 | 3 4 2 |
+------------------+----------------+------------+
| 289 1 489 | 5 234* 24* | 7 68 36 |
| 5 3 6 | 78 19 79 | 18 2 4 |
| 28* 24* 7 | 38* 1234 6 | 5 9 13 |
+------------------+----------------+------------+
| 7 8 2 | 6 49 1 | 49 3 5 |
| 369 4569 1 | 2 3459 4579 | 49 67 8 |
| 369 4569 349 | 37 8 4579 | 2 167 167 |
+------------------+----------------+------------+
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Not sure what this is, but the 5 * cells (containing 2348) form a pattern which eliminates 24 from r6c5 and solves the puzzle |
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TomC
Joined: 30 Oct 2020
Posts: 358
Location: Wales
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| Posted: Sat Sep 18, 2021 6:39 am Post subject: |
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| And it can eliminate 2 and 4 from r4c13 |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Sat Sep 18, 2021 8:42 am Post subject: |
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Nicely done Tom. One way of explaining this (others exist I am sure) is an ALS with two digit eliminations which is reasonably rare.
Set A {2,3,4,8}
Set B {2,3,4}
The restricted common digit is 3 (r4c5,r6c4)
The 2's and 4's in red can see all the other 2's and 4's in A & B so are eliminated. These are the common candidates.
Good spot! |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Sat Sep 18, 2021 9:39 am Post subject: |
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I guess you could also view this as a slightly unconventional WXYZ wing - the 4 candidates are in 5 cells.
You can view the <38> in r6c4 as a hinge.
If it’s 3 then you create a <24> locked pair in r4c56 eliminating all the 2s and 4s in the red cells.
If it’s 8 then r6c12 become 2 and 4 making the same eliminations as above. |
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TomC
Joined: 30 Oct 2020
Posts: 358
Location: Wales
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| Posted: Sat Sep 18, 2021 9:59 am Post subject: |
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Indeed, many ways to describe this.
My first thought was to say that if r6c5 is either 2 or 4 then r6c4 would always be 3 leading to a contradiction in box 5
I then noticed the other elimination of 24's in box 4 |
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Mogulmeister
Joined: 03 May 2007
Posts: 1151
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| Posted: Sat Sep 18, 2021 10:50 am Post subject: |
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Also a contradiction with the
ANP (24=3)r4c56-(3=8)r6c4 etc etc
Which puts a contradictory 3 in r4c9. |
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