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ZeroAssoluto
Joined: 05 Feb 2017 Posts: 927 Location: Rimini, Italy
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Posted: Sat Jan 22, 2022 10:21 am Post subject: Jan 22 VH |
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Hi everyone,
Code: |
+--------------+--------------+---------------+
| 5 24 234 | 7 134 12 | 9 8 6 |
| 79 2478 6 | 39 34589 258 | 357 2357 1 |
| 1 278 2389 | 6 3589 258 | 4 2357 25 |
+--------------+--------------+---------------+
| 79 2457 2459 | 39 3589 6 | 358 1 2458 |
| 8 1 25 | 4 35 7 | 6 235 9 |
| 6 3 459 | 2 1589 158 | 578 57 458 |
+--------------+--------------+---------------+
| 4 58 7 | 58 2 9 | 1 6 3 |
| 3 6 58 | 1 7 4 | 2 9 58 |
| 2 9 1 | 58 6 3 | 58 4 7 |
+--------------+--------------+---------------+
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Play this puzzle online at the Daily Sudoku site
first step
AIC in r4c4
r4c4=9 and -9 in r4c13,r6c5
r4c4=3 r5c8=3 r4c9=2 r3c9=5 r8c9=8 r3c3=8 r3c5=9 r6c3=9 and -9 in r4c13.r6c5
Code: |
+----------+------------+-------------+
| 5 24 3 | 7 14 12 | 9 8 6 |
| 9 248 6 | 3 458 258 | 57 257 1 |
| 1 7 28 | 6 9 258 | 4 3 25 |
+----------+------------+-------------+
| 7 25 4 | 9 58 6 | 3 1 258 |
| 8 1 25 | 4 3 7 | 6 25 9 |
| 6 3 9 | 2 158 158 | 578 57 4 |
+----------+------------+-------------+
| 4 58 7 | 58 2 9 | 1 6 3 |
| 3 6 58 | 1 7 4 | 2 9 58 |
| 2 9 1 | 58 6 3 | 58 4 7 |
+----------+------------+-------------+
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Play this puzzle online at the Daily Sudoku site
second step
XY-Wing 2,5,8 in r3c39,r8c3 and -5 in r8c9
Ciao Gianni |
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dongrave
Joined: 06 Mar 2014 Posts: 568
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Posted: Sun Jan 23, 2022 1:26 pm Post subject: |
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Using just standard VH moves I think you have to use the X-Wing on 9's in cols 1 and 4, the X-Wing on 3's in cols 4 and 7, a 578 XYZ-Wing with pivot at r6c7, and then a 58-3 XY-Wing with pivot at r4c5. After applying the X-Wing on 3's I also saw a 257 XYZ-Wing with pivot at r2c8 but it doesn't look like that was necessary. |
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TomC
Joined: 30 Oct 2020 Posts: 358 Location: Wales
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Posted: Sun Jan 23, 2022 1:46 pm Post subject: |
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An alternative second step to Gianni's post
<25> W wing in r3c9 and r5c3 gives -2 in r3c3 |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Sun Jan 23, 2022 6:17 pm Post subject: |
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Another second step using Gianni’s grid is the <248> ANP in r12c2.
If ANP is true then r4c2 = 5 r5c3 <> 5 r8c3 = 5 and r8c9 < > 5
If ANP is false then r2c2 = 8 r3c3 = 2 r3c9 = 5 and r8c9 < > 5 |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Mon Jan 24, 2022 7:19 am Post subject: |
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Don,
Given the variable nature of the grading algorithm, what grade do you think this one was at ? |
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peter urhegyi
Joined: 26 Oct 2020 Posts: 28
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Posted: Mon Jan 24, 2022 9:09 am Post subject: 5 step daily sudoku 22-01-2022 |
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Dongrave found 4 of the 5 steps:
1)x-wing on 9's in cols 1&4
2)x-wing on 3's in cols 4&7
3)xyz-wing 578 with pivot at R6C7 (R4C7!=5)
4)xy-wing 58-3 with pivot at R4C5 (R4C4!=3 and R5C8!=3)
I needed one more step:
5a)xy-wing 28-5 with pivot at R3C3 (R8C9!=5 )
or
5b)xy-wing 25-8 with pivot at R3C9 (R8C3!=8 )
Last edited by peter urhegyi on Mon Jan 24, 2022 9:31 am; edited 4 times in total |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Mon Jan 24, 2022 9:23 am Post subject: |
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Thanks Peter. |
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TomC
Joined: 30 Oct 2020 Posts: 358 Location: Wales
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Posted: Mon Jan 24, 2022 10:37 am Post subject: |
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Another second step using Gianni’s grid is -8 in r4c9 as this is needed to avoid the <57> UR in r26c78
This has certainly been the trickiest VH for a while! |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Mon Jan 24, 2022 11:21 am Post subject: |
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I don't know for sure, but if that had appeared in The Telegraph it might well have been deemed a diabolical ? |
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Mogulmeister
Joined: 03 May 2007 Posts: 1151
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Posted: Mon Jan 24, 2022 11:38 am Post subject: |
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TomC wrote: | Another second step using Gianni’s grid is -8 in r4c9 as this is needed to avoid the <57> UR in r26c78
This has certainly been the trickiest VH for a while! |
Good spot Tom |
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dongrave
Joined: 06 Mar 2014 Posts: 568
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Posted: Mon Jan 24, 2022 2:32 pm Post subject: |
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Thanks for pointing that out Peter! I must have made an error somewhere along the way! I had a tough time with that one! |
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