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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Mon Nov 26, 2007 5:37 pm Post subject: Interesting |
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If today's VH went by took quickly, here is one that uses many techniques. Interesting.
Earl
| Code: | *--------------------------------------------------------------------*
| 4 18 57 | 1678 2 1689 | 3 58 5678 |
| 1578 6 9 | 1378 1378 18 | 1478 2 4578 |
| 1278 138 237 | 5 13678 4 | 1678 9 678 |
|----------------------+----------------------+----------------------|
| 78 5 47 | 9 1478 18 | 2 6 348 |
| 3 48 2467 | 2678 45678 2568 | 489 458 1 |
| 268 9 1 | 268 4568 3 | 48 7 458 |
|----------------------+----------------------+----------------------|
| 1569 2 356 | 4 13568 7 | 689 38 3689 |
| 69 7 346 | 2368 368 268 | 5 1 34689 |
| 156 134 8 | 136 9 156 | 467 34 2 |
*--------------------------------------------------------------------* |
(Edited by Marty to align grid) |
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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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| Posted: Mon Nov 26, 2007 5:46 pm Post subject: Interesting |
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Here is the original grid.
I often cannot get the grids to line up correclty.
Earl
| Code: |
+-------+-------+-------+
| 4 . . | . 2 . | 3 . . |
| . 6 9 | . . . | . 2 . |
| . . . | 5 . 4 | . 9 . |
+-------+-------+-------+
| . 5 . | 9 . . | 2 6 . |
| 3 . . | . . . | . . 1 |
| . 9 1 | . . 3 | . 7 . |
+-------+-------+-------+
| . 2 . | 4 . 7 | . . . |
| . 7 . | . . . | 5 1 . |
| . . 8 | . 9 . | . . 2 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Mon Nov 26, 2007 9:06 pm Post subject: |
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hi earl,
nice puzzle, first real move is the x-wing on the 4 removes 4 from r5c5, then a number of ways you can from here. either an xy-chain or if you look at the 5's in rows 2, 6 and 7 and columns 1, 5 and 9, there is a finned sword fish, of course it doesn't do much, just takes out the 5 in r9c1. finding a sword fish is pretty interesting to me.
after that a finned x-wing on the 6's in rows 5 and 8 and columns 3 and 6 takes out 6 in r8c1.
the 6's look promising after that. but I think a couple more chains will have to do the trick. |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Mon Nov 26, 2007 9:59 pm Post subject: |
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After the X-wing on <4>, coloring on <4> solves R6C7 as <8>. After that, a couple of XY-wings finish it off.
Keith |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Thu Nov 29, 2007 10:19 pm Post subject: |
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Keith,
How did you color <4>? I'm not seeing it. |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Thu Nov 29, 2007 10:22 pm Post subject: |
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There's an alternative to that Finned Swordfish. The <5> at R7C5 can see both ends of the strong link in C3 via ERs in Boxes 3, 6 and 5:
| Code: | +---------------+-------------------+---------------+
| 4 18 A57 | 1678 2 9 | 3 58 5678 |
| 1578 6 9 | 1378 1378 18 |e148 e2 4578 |
| 1278 138 237 | 5 1678 4 |e168 e9 678 |
+---------------+-------------------+---------------+
| 78 5 47 |e9 148 e18 |e2 e6 3 |
| 3 48 26 | 2678 5678 256 | 9 458 1 |
| 26 9 1 |e268 4568 e3 |e48 e7 458 |
+---------------+-------------------+---------------+
| 1569 2 a356 | 4 #13-568 7 | 68 38 689 |
| 69 7 346 | 2368 368 26 | 5 1 4689 |
| 156 134 8 | 136 9 56 | 7 34 2 |
+---------------+-------------------+---------------+ |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Fri Nov 30, 2007 12:29 am Post subject: |
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storm_norm's <6> elimination in R8C1 can also be seen as due to a {26} W-Wing (or Remote Pair) in R6C1 and R8C6. Then, more can be done with the <6>s...
There is a Finned X-Wing in C36 where the fin is visible to R8C4 via ERs in Boxes 9, 3 and 2 eliminating <6> in R8C4. However, this step isn't necessary.
Instead, there is a Color Wing (Multi-Coloring) that employs grouped coloring on the end of one chain:
| Code: | +------------------+-----------------+---------------+
| 4 18 57 | 1678 2 9 | 3 58 5678 |
| 1578 6 9 | 1378 1378 18 | 148 2 4578 |
| 1278 138 237 | 5 1678 4 | 168 9 678 |
+------------------+-----------------+---------------+
| 78 5 47 | 9 148 18 | 2 6 3 |
| 3 48 26r | 78 578 26g| 9 458 1 |
| 26 9 1 | 268 4568 3 | 48 7 458 |
+------------------+-----------------+---------------+
|#15-6 2 356(g)| 4 1368 7 | 68 38 9 |
| 9 7 346(g)| 2368 368 26r| 5 1 468 |
| 16R 134 8 | 136G 9 5 | 7 34 2 |
+------------------+-----------------+---------------+ |
The r-G "Bridge" is in Box 8. Eliminations occur between R and g. The grouped coloring is shown in parentheses in Box 7 C3. <6> is removed from R7C1.
The resulting strong link in C1 completes a color loop back to Box 8 eliminating <6> from R7C5 and R8C45. (This is why that Finned X-Wing with the ERs isn't necessary.)
Then, there is another Color Wing:
| Code: | +---------------+---------------+---------------+
| 4 18 57 |G1678 2 9 | 3 58 R5678 |
| 1578 6 9 | 1378 1378 18 | 148 2 4578 |
| 1278 138 237 | 5 1678 4 | 168 9 678 |
+---------------+---------------+---------------+
| 78 5 47 | 9 148 18 | 2 6 3 |
| 3 48 g26 | 78 578 r26 | 9 458 1 |
|r26 9 1 | 268 4568 3 | 48 7 458 |
+---------------+---------------+---------------+
| 15 2 356 | 4 138 7 | 68 38 9 |
| 9 7 346 | 238 38 g26 | 5 1 #4-68 |
|g16 134 8 |r136 9 5 | 7 34 2 |
+---------------+---------------+---------------+ |
The r-G "Bridge" is in C4. <6> is removed from R8C9.
After this, two XY Wings complete the puzzle. The first pivots at R8C9 and eliminates a <3>. The second pivots at R7C8 and eliminates <5>. |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Fri Nov 30, 2007 12:36 am Post subject: |
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Hi,
I am new at Sudoku and to this site, but how been following the discussions for awhile to learn.
After the basics, I found a finned x-wing to eliminate <2> at r5c3, then another finned x-wing to eliminate <1> at r3c2 & r2c4. Then a xyz_wing with pivot atr3c1 eliminated the <8> at r2c1. Finally a xy-wing with pivot at r9c2 eliminated <3> from r8c45 which solved the puzzle.
I have no idea if all these moves were required or even if all were truly correct but they worked.
Ted |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Fri Nov 30, 2007 2:25 am Post subject: |
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Hi Ted,
Welcome again! (I just replied to one of your posts on another thread.)
I believe you were lucky in this case. Here's the grid after basics:
| Code: | +--------------+-----------------+--------------+
| 4 18 57 | 1678 2 9 | 3 58 5678 |
| 1578 6 9 | 1378 1378 18 | 148 2 4578 |
| 1278 138 237 | 5 1678 4 | 168 9 678 |
+--------------+-----------------+--------------+
| 78 5 47 | 9 148 18 | 2 6 3 |
| 3 48 26 |x2678 45678 x256 | 9 458 1 |
| 26 9 1 |f268 4568 3 | 48 7 458 |
+--------------+-----------------+--------------+
| 1569 2 356 | 4 13568 7 | 68 38 689 |
| 69 7 346 |x2368 368 x26 | 5 1 4689 |
| 156 134 8 | 136 9 56 | 7 34 2 |
+--------------+-----------------+--------------+ |
I have marked what you are probably considering to be your Finned X-Wing. Any "victim" cells must be able to "see" both the potential X-Wing and the Fin. The only such cell here is R5C5, which contains no <2>. The <2> in R5C3 can see the potential X-Wing but cannot see the Fin; so, it cannot be removed in this way.
A finned fish (such as Finned X-Wing) alone can only eliminate candidates within cells belonging to a single Box, the Box shared with the fin. Your <1> eliminations in R3C2 and R2C4 are in two different Boxes. So, that's not possible with a Finned X-Wing.
Don't get discouraged. These are "learning opportunities"! |
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