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ZeroAssoluto
Joined: 05 Feb 2017 Posts: 933 Location: Rimini, Italy
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Posted: Fri May 26, 2017 10:38 pm Post subject: May 27 VH |
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Hi everyone,
Code: |
+-------------+--------------+-------------+
| 9 5 28 | 1 3 6 | 7 28 4 |
| 4 27 1 | 2578 257 9 | 6 3 28 |
| 6 237 2378 | 278 247 48 | 1 5 9 |
+-------------+--------------+-------------+
| 3 279 6 | 2589 1 58 | 259 4 78 |
| 1 8 29 | 4 259 7 | 3 6 25 |
| 5 4 279 | 2389 6 38 | 29 78 1 |
+-------------+--------------+-------------+
| 8 6 5 | 79 79 2 | 4 1 3 |
| 27 1 39 | 6 45 345 | 8 279 257 |
| 27 39 4 | 35 8 1 | 25 279 6 |
+-------------+--------------+-------------+
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Play this puzzle online at the Daily Sudoku site
XY-Wing 2,7,8 in r2c29, r4c9 and -7 in r4c2.
Ciao Gianni |
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George Woods
Joined: 28 Mar 2006 Posts: 304 Location: Dorset UK
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Posted: Sat May 27, 2017 10:47 am Post subject: Almost an XY wing |
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The pivot at r6c8 denies a 2 to r1c3 either via r1c8 or the pair of 29 at r56c3 so it is a kind of xy wing according to its mechanics but not apure XY I wonder what it is called a compound XY wing?
Last edited by George Woods on Sat May 27, 2017 1:18 pm; edited 1 time in total |
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JC Van Hay
Joined: 13 Jun 2010 Posts: 494 Location: Charleroi, Belgium
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Posted: Sat May 27, 2017 11:43 am Post subject: |
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Like the XY-Wing, this is an ALS-XZ Rule. |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat May 27, 2017 12:19 pm Post subject: Re: Almost an XY wing |
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George Woods wrote: | The pivot at r6c8 denies a 2 to r1c3 either via r1c7 or the pair of 29 at r46c3 so it is a kind of xy wing according to its mechanics but not apure XY I wonder what it is called a compound XY wing? |
George, could you enlighten me? I don't see the 29 pair or anything in r1c7?
Quote: |
Like the XY-Wing, this is an ALS-XZ Rule. |
JC, what is your X and Z value and what cells are being used? |
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George Woods
Joined: 28 Mar 2006 Posts: 304 Location: Dorset UK
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Posted: Sat May 27, 2017 1:13 pm Post subject: |
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Sorry I got it wrong I meant r1c8 not r1c7 for one wing that becomes 2 if r6c8 is 8 whilst if r6c8 is 7 then r6c3 becomes 29 so that is equivalen to a wing being 2 since it denies a 2 o r1c3 |
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JC Van Hay
Joined: 13 Jun 2010 Posts: 494 Location: Charleroi, Belgium
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Posted: Sat May 27, 2017 1:45 pm Post subject: Re: Almost an XY wing |
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Marty R. wrote: | JC, what is your X and Z value and what cells are being used? |
Code: | +----------------+----------------+----------------+
| 9 5 8-2 | 1 3 6 | 7 (28) 4 |
| 4 27 1 | 2578 257 9 | 6 3 28 |
| 6 237 2378 | 278 247 48 | 1 5 9 |
+----------------+----------------+----------------+
| 3 279 6 | 2589 1 58 | 259 4 78 |
| 1 8 (29) | 4 259 7 | 3 6 25 |
| 5 4 (279) | 2389 6 38 | 29 (78) 1 |
+----------------+----------------+----------------+
| 8 6 5 | 79 79 2 | 4 1 3 |
| 27 1 39 | 6 45 345 | 8 279 257 |
| 27 39 4 | 35 8 1 | 25 279 6 |
+----------------+----------------+----------------+ | ALS-XZ Rule : [(2=8=7)r16c8-(7=92)r65c3]-2r1c3
Note : X=7, Z=2 in the ALS (278)r16c8 and (279)r56c3 |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat May 27, 2017 3:37 pm Post subject: |
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Quote: | I wonder what it is called a compound XY wing?
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George, it looks to me like a Forcing Chain with each number in a bivalue cell (r6c8) producing the same outcome. |
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Marty R.
Joined: 12 Feb 2006 Posts: 5770 Location: Rochester, NY, USA
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Posted: Sat May 27, 2017 3:42 pm Post subject: |
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Quote: | ALS-XZ Rule : [(2=8=7)r16c8-(7=92)r65c3]-2r1c3
Note : X=7, Z=2 in the ALS (278)r16c8 and (279)r56c3 |
Nice, JC. I've used the ALS-XZ rule about a half-dozen times, but can no longer find them. |
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