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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Sat Jan 02, 2010 3:41 pm Post subject: Jan 2 DB |
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The Jan 2 DB defied a knockout punch, but fell to the old one-two.
A Solution: x-wing (9) followed by an xy-wing (149)
Earl
| Code: |
+-------+-------+-------+
| . . . | 6 . . | . 7 . |
| . . 6 | . . 2 | . . 4 |
| 1 3 . | . . . | . . 5 |
+-------+-------+-------+
| . . . | . 2 6 | 1 5 . |
| 9 . . | 1 . 8 | . . 2 |
| . 1 2 | 9 5 . | . . . |
+-------+-------+-------+
| 7 . . | . . . | . 6 3 |
| 2 . . | 7 . . | 5 . . |
| . 8 . | . . 9 | . . . |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jan 02, 2010 4:39 pm Post subject: |
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Earl, I always enjoy your metaphorical descriptions of puzzle solutions!!  |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Jan 02, 2010 7:48 pm Post subject: |
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I have no idea what to call this, but here goes.
After basics: | Code: | +----------------+----------------+----------------+
| 48 2 489 | 6 1349 5 | 389 7 18 |
| 5 79 6 | 38 1379 2 | 389 1389 4 |
| 1 3 4789 | 48 479 47 | 6 2 5 |
+----------------+----------------+----------------+
| 348 47 478 | 34 2 6 | 1 5 9 |
| 9 6 5 | 1 347 8 | 347 34 2 |
| 34 1 2 | 9 5 347 | 3478 348 6 |
+----------------+----------------+----------------+
| 7 5 149 | 2 8 14 | 49 6 3 |
| 2 49 1349 | 7 6 134 | 5 1489 18 |
| 6 8 134 | 5 34 9 | 2 14 7 |
+----------------+----------------+----------------+ |
Take a look at R9C5. If R9C5 is 3, R2C4 is 3, R4C4 is not 3, it must be 4. So, R9C5 and R4C4 are pincers on 4, taking out 4 in R5C5.
Using the same idea: If R3C6 is 7, R4C2 is 4. So, R3C6 and R4C2 are pincers on 4. But, if R4C2 is 4, so is R3C4. Eliminating 4 in R1C5 and R3C5.
Thus, R9C5 is 4, and the puzzle is solved. 
I've been having some success with this idea: Start grouped coloring in a bivalue cell, and see where it may take you. (It's how I look for M-wings.)
If anyone has seen this before, or has a name for it, I'd appreciate the reference.
(I suppose these are W-wings with grouped links, but I have an issue with that idea.)
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jan 02, 2010 7:58 pm Post subject: |
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| Quote: | | (I suppose these are W-wings with grouped links, but I have an issue with that idea.) |
Keith, what is your issue with the W-Wing terminology? With the 34 it looks like a W with a grouped link and with the 47 it appears to be a pure W, if you will, with one strong link, not grouped. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Jan 02, 2010 8:43 pm Post subject: |
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Marty,
My issue (I'll have to think about it) is with grouped links, not with W-wings.
I sort of think that a grouped link only exists with respect to the chain it is in, not like a regular strong link.
Also, grouped links are not, generally, reversible.
Marty,
As I said, I'll have to think about it. Certainly, a half M-wing is built on non-reversible grouped coloring.
Keith |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sat Jan 02, 2010 10:30 pm Post subject: |
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| If I didn't see the W-Wings and did what you did, I'd call them XY-Chains. However, purists won't like that because the chain doesn't use bivalue cells exclusively. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sat Jan 02, 2010 11:43 pm Post subject: |
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| Quote: | | I have no idea what to call this, but here goes. |
Keith, are you feeling alright? |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Sat Jan 02, 2010 11:59 pm Post subject: |
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| storm_norm wrote: | | Quote: | | I have no idea what to call this, but here goes. |
Keith, are you feeling alright? |
No, it's 10 F and windy. I'm cold!  |
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Marty R.
Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
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| Posted: Sun Jan 03, 2010 12:41 am Post subject: |
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| Quote: | | No, it's 10 F and windy. I'm cold! |
You'll probably warm up after the Lions maul the Bears.  |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Sun Jan 03, 2010 6:59 am Post subject: |
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| Code: | +-----------------+-----------------+-------------------+
| (48) 2 489 | 6 1349 5 | 389 7 -8(1) |
| 5 79 6 | 38 1379 2 | 389 1389 4 |
| 1 3 4789 | 48 479 47 | 6 2 5 |
+-----------------+-----------------+-------------------+
| 348 47 478 | 34 2 6 | 1 5 9 |
| 9 6 5 | 1 347 8 | 347 34 2 |
| (34) 1 2 | 9 5 47(3) | 3478 348 6 |
+-----------------+-----------------+-------------------+
| 7 5 149 | 2 8 14 | 49 6 3 |
| 2 49 1349 | 7 6 14(3) | 5 1489 8(1) |
| 6 8 4(13) | 5 4(3) 9 | 2 4(1) 7 |
+-----------------+-----------------+-------------------+ |
(1)r1c9 = (1)r8c9 - (1)r9c8 = (1-3)r9c3 = (3)r9c5 - (3)r8c6 = (3)r6c6 - (3=4)r6c1 - (4=8)r1c1; r1c9 <> 8
for a single bullet |
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