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[ArkieTech]

Code: Select all

 *-----------*
 |.94|1.8|..7|
 |...|..2|4.5|
 |..3|...|.89|
 |---+---+---|
 |...|87.|..2|
 |.68|2.5|79.|
 |2..|.13|...|
 |---+---+---|
 |94.|...|5..|
 |6.5|4..|...|
 |8..|5.1|94.|
 *-----------*


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[Leren]

Code: Select all

*--------------------------------------------------------------------------------*
| 5       9       4        | 1       36      8        | 236     236     7        |
| 17      8       6        | 379     39      2        | 4       13      5        |
| 17      2       3        | 67      5       4        | 16      8       9        |
|--------------------------+--------------------------+--------------------------|
| 4       15     e-19      | 8       7      d69       | 36      356     2        |
| 3       6       8        | 2       4       5        | 7       9       1        |
| 2       57      79       | 69      1       3        | 8       56      4        |
|--------------------------+--------------------------+--------------------------|
| 9       4      a12       | 36      2368   c67       | 5      b127     368      |
| 6       13      5        | 4       2389    79       | 12      127     38       |
| 8       37      27       | 5       236     1        | 9       4       36       |
*--------------------------------------------------------------------------------*

(1)r7c3 = (1-7)r7c8 = (7-6) r7c6 =(6-9) r4c6 = r4c3 => r4c3<1>

Leren

[ArkieTech]

Code: Select all

 *-----------------------------------------------------------*
 | 5     9     4     | 1     36    8     | 236   236   7     |
 | 17    8     6     | 379   39    2     | 4     13    5     |
 | 17    2     3     | 67    5     4     | 16    8     9     |
 |-------------------+-------------------+-------------------|
 | 4     15   b19    | 8     7    a69    | 36    356   2     |
 | 3     6     8     | 2     4     5     | 7     9     1     |
 | 2     57    79    | 69    1     3     | 8     56    4     |
 |-------------------+-------------------+-------------------|
 | 9     4    c12    |c36   c2368  7-6   | 5     127  c368   |
 | 6     13    5     | 4     2389  79    | 12    127   38    |
 | 8     37    27    | 5     236   1     | 9     4     36    |
 *-----------------------------------------------------------*
(6=9)rc6-(9=1)r4c3-(1=386r7c459)r7c3459  => -6r7c6; stte

[Marty R.]

Code: Select all

+----------+-------------+-------------+
| 5  9  4  | 1   36   8  | 236 236 7   |
| 17 8  6  | 379 39   2  | 4   13  5   |
| 17 2  3  | 67  5    4  | 16  8   9   |
+----------+-------------+-------------+
| 4  15 19 | 8   7    69 | 36  356 2   |
| 3  6  8  | 2   4    5  | 7   9   1   |
| 2  57 79 | 69  1    3  | 8   56  4   |
+----------+-------------+-------------+
| 9  4  12 | 36  2368 67 | 5   127 368 |
| 6  13 5  | 4   2389 79 | 12  127 38  |
| 8  37 27 | 5   236  1  | 9   4   36  |
+----------+-------------+-------------+


Play this puzzle online at the Daily Sudoku site

Best I could do was a mile-long chain wherein r2c8=3 created a 1 in r4c2 and then a transport from r2c8 allowed for an elimination.

1r8c7=1r78c8-(1=3)r2c8-(3=9)r2c5-r8c5=r8c6-r4c6=r6c4-(9=7)r6c3-(7=5)r6c2-(5=1)r4c2=>r8c2<>1

[Leren]

ArkieTech wrote: (6=9)rc6-(9=1)r4c3-(1=386r7c459)r7c3459 => -6r7c6;

Shouldn't this move be written as (6=9)r4c6-(9=1)r4c3-(2=368r7c459)r7c3459 => -6r7c6

Leren

[ArkieTech]

ArkieTech wrote: (6=9)rc6-(9=1)r4c3-(1=386r7c459)r7c3459 => -6r7c6;

Shouldn't this move be written as (6=9)r4c6-(9=1)r4c3-(2=368r7c459)r7c3459 => -6r7c6

Leren

(6=9)r4c6-(9=1)r4c3-(2=368r7c459)r7c3459 => -6r7c6 ????

Column 459 form a 368 triple when r7c3 is not 1

[David P Bird]

Leren, these are the options for navigating row 7 as I see them:

A) (6=9)r4c6 – (9=1)r4c3 – (1)r7c3 = (1-7)r7c8 = (7)r7c6 => r7c6 <> 6

B) (6=9)r4c6 – (9=1)r4c3 – (1=2)r7c3 – (238=6)ANS:r7c459 => r7c6 <> 6

C) (6=9)r4c6 – (9=1)r4c3 – (1=2368)ANS:r7c3459 => r7c6 <> 6

Which one you favour depends on your objectives. In my case it's to make the logic as easy as possible to follow so I would choose A). (Nowadays the ANS descriptor seems to have become optional.)

ArkieTech, when I came to post I saw that you beat me to it. However your response looks rather like a case of the pot calling the kettle black!

(6=9)rc6-(9=1)r4c3-(1=386r7c459)r7c3459 => -6r7c6; stte

I believe this should be (6=9)r4c6-(9=1)r4c3-(1=2386r7c459)r7c3459 => -6r7c6; stte
This is option C) above in your preferred notation style.

For the possible benefit of others; the 4 Almost Naked Set cells r7c3459 together hold 5 candidates which should all be identified in its notation. Consequently only one of them can be false. To validate the strong inference for themselves readers need to check these counts and also that r7c3 is the only cell in the set that can hold (1).

[daj95376]

Dan, et. al.

I would have written your chain as:

(6=9)r4c6 - (9=1)r4c3 - (1=2)r7c3 - (2=386)r7c459 => -6r7c6; stte

I'm not a fan of the "transition point" in an ALS being a bivalue cell.



An alternative:

(638=2)r7c459 - (2=36)r7c4,r9c5 => r7c6<>6

[ArkieTech]

An alternative:

(638=2)r7c459 - (2=36)r7c4,r9c5 => r7c6<>6

Very nice Thanks Danny.