Diabolical puzzle

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Diabolical puzzle

Postby Arutha2321 » Mon Jan 07, 2008 11:05 am

Hello. This puzzle is called "Diabolical one" and now I can see why. Please help!

2 1 4 | 3 x x | x 9 x
x x 3 | 4 x x | 8 x x
6 8 x | x x 2 | x 3 4
-----------------------
x x x | x 2 6 | x x 7
x x 6 | 7 4 x | 5 x x
4 7 2 | 8 5 x | x 6 x
-----------------------
3 2 x | x x x | x x 9
x 4 8 | x x 7 | 2 5 x
x 6 x | 2 x 4 | x 1 8

Note: Numbers written in italic are solved ones.
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Postby tarek » Mon Jan 07, 2008 11:50 am

Not sure exactly where you've reached in your solution......


A PM grid in these cases would be of great help....

from this position a sashimi finned x-wing or an xy wing to name some techniques that could solve this....

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Postby Arutha2321 » Mon Jan 07, 2008 12:05 pm

ahem, what is a PM grid?
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Postby tarek » Mon Jan 07, 2008 1:02 pm

I was referring to the Pencilmark grid.....

Please refere to the following post:
http://forum.enjoysudoku.com/viewtopic.php?t=2664
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Postby ArkieTech » Mon Jan 07, 2008 1:21 pm

Arutha2321 said:
what is a PM grid?


Code: Select all
 *-----------------------------------------------------------*
 | 2     1     4     | 3     678   58    | 67    9     56    |
 | 579   59    3     | 4     1679  159   | 8     27    1256  |
 | 6     8     579   | 159   179   2     | 17    3     4     |
 |-------------------+-------------------+-------------------|
 | 1589  359   159   | 19    2     6     | 1349  48    7     |
 | 189   39    6     | 7     4     139   | 5     28    123   |
 | 4     7     2     | 8     5     139   | 139   6     13    |
 |-------------------+-------------------+-------------------|
 | 3     2     17    | 156   18    158   | 467   47    9     |
 | 19    4     8     | 169   139   7     | 2     5     36    |
 | 579   6     579   | 2     39    4     | 37    1     8     |
 *-----------------------------------------------------------*

This is a pencil mark grid.
Look for a sashimi x on 7
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Postby Arutha2321 » Mon Jan 07, 2008 2:02 pm

Sashimi? Sorry Im new to this forum so I dont know the terms yet.
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Postby ArkieTech » Mon Jan 07, 2008 3:53 pm

Arutha2321
Code: Select all
 *-----------------------------------------------------------*
 | 2     1     4     | 3     678   58    | 67    9     56    |
 |*759   59    3     | 4     1679  159   | 8    *72    1256  |
 | 6     8     579   | 159   179   2     | 17    3     4     |
 |-------------------+-------------------+-------------------|
 | 1589  359   159   | 19    2     6     | 1349  48    7     |
 | 189   39    6     | 7     4     139   | 5     28    123   |
 | 4     7     2     | 8     5     139   | 139   6     13    |
 |-------------------+-------------------+-------------------|
 | 3     2    -71    | 156   18    158   | 467  *74    9     |
 | 19    4     8     | 169   139   7     | 2     5     36    |
 |*759   6     579   | 2     39    4     | 37    1     8     |
 *-----------------------------------------------------------*

Can you logically show where r7c3 cannot be a 7?

It is singles from there.

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Diabolical puzzle

Postby bingham » Thu Jan 10, 2008 2:43 am

An even shorter loop results from showing that r1c7<>7. It probably has some fishy name!
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Postby Carcul » Thu Jan 10, 2008 10:50 pm

[r5c8]=8=[r5c1]=1=[r4c13]-1-[r4c4]-9-[r56c6]=9|2=[r5c9]-2-[r5c8],

=> r5c8<>2.
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Postby daj95376 » Fri Jan 11, 2008 1:05 am

No fish present for [r1c7]<>7. However, there is tarek's ...

Code: Select all
# XY-Wing  [r9c7]/[r1c7]+[r8c9]   <> 6    [r1c9],[r2c9],[r7c7]
 +--------------------------------------------------------------------+
 |  2      1      4     |  3      678    58    | *67     9      5-6   |
 |  579    59     3     |  4      1679   159   |  8      27     125-6 |
 |  6      8      579   |  159    179    2     |  17     3      4     |
 |----------------------+----------------------+----------------------|
 |  1589   359    159   |  19     2      6     |  1349   48     7     |
 |  189    39     6     |  7      4      139   |  5      28     123   |
 |  4      7      2     |  8      5      139   |  139    6      13    |
 |----------------------+----------------------+----------------------|
 |  3      2      17    |  156    18     158   |  47-6   47     9     |
 |  19     4      8     |  169    139    7     |  2      5     *36    |
 |  579    6      579   |  2      39     4     | *37     1      8     |
 +--------------------------------------------------------------------+
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