Please help with strategy

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Please help with strategy

Postby bananafish » Wed May 25, 2016 5:21 pm

Hi folks,

Please help with the following puzzle. I can't find figure out a strategy to solve the next number.

Thanks and I appreciate your help!
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Re: Please help with strategy

Postby JasonLion » Wed May 25, 2016 10:40 pm

.2.567.49796..1.....5..9..68.9654.2.5.297..64..421.9.52...9........8..929..7.2...

One approach is to use an ALS-XZ.
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Re: Please help with strategy

Postby SteveG48 » Thu May 26, 2016 1:22 am

You're heading for trouble. You have an incorrect elimination in r7c3.
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Re: Please help with strategy

Postby JC Van Hay » Thu May 26, 2016 7:14 am

Code: Select all
+---------------------+-----------------+------------------------+
| 13    2        138  | 5    6       7  | 138       4       9    |
| 7     9        6    | 348  3-4(2)  1  | 38(25)    38(5)   38   |
| 134   348      5    | 38   23      9  | 12378     1378    6    |
+---------------------+-----------------+------------------------+
| 8     137      9    | 6    5       4  | 137       2       137  |
| 5     13       2    | 9    7       38 | 138       6       4    |
| 36    367      4    | 2    1       38 | 9         378     5    |
+---------------------+-----------------+------------------------+
| 2     34568    1378 | 134  9       56 | 1345678   13578   1378 |
| 1346  3456     137  | 134  8       56 | 134567    9       2    |
| 9     38(456)  138  | 7    3(4)    2  | 138(456)  138(5)  138  |
+---------------------+-----------------+------------------------+
[HP(25)r2c57=5r2c8-5r9c8=HT(456)r9c257]-4r2c5=4r9c5
or
[2r2c5==5r2c8-5r9c8==4r9c5]-4r2c5=4r9c5
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Re: Please help with strategy

Postby Leren » Fri May 27, 2016 8:34 am

Here's the ALS move that Jason was referring to :

Code: Select all
*--------------------------------------------------------------------------------*
| 13      2       138      | 5       6       7        | 138     4       9        |
| 7       9       6        |a348     23-4    1        | 2358   a358    a38       |
| 134     348     5        | 38      23      9        | 12378   1378    6        |
|--------------------------+--------------------------+--------------------------|
| 8       137     9        | 6       5       4        | 137     2       137      |
| 5       13      2        | 9       7       38       | 138     6       4        |
| 36      367     4        | 2       1       38       | 9       378     5        |
|--------------------------+--------------------------+--------------------------|
| 2       34568   1378     | 13-4    9       56       | 1345678 13578   1378     |
| 1346    3456    137      | 13-4    8       56       | 134567  9       2        |
| 9       34568  b138      | 7      b34      2        | 134568 b1358   b138      |
*--------------------------------------------------------------------------------*

ALS XZ Rule: X = 5, Z = 4: (4=5) r2c489 - (5=4) r9c3589 => - 4 r2c5, r78c4.

After that the puzzle solves with a pointing pair of 1's in Column 1, a claiming triple of 3's in Column 3 Box 7, a naked triple 456 in Row 8 and singles from there.

r7c3 solves to 1, so you have made an error at some point leading to your diagram, as Steve pointed out.

Leren
Last edited by Leren on Wed Jun 01, 2016 2:41 am, edited 1 time in total.
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Re: Please help with strategy

Postby bananafish » Tue May 31, 2016 11:27 pm

Thank you! Very much appreciate sharing the strategies and pointing out the problems! Looks like I have some Sudoku strategy studying to do. :)
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