The New Sudoku Players' Forum

[jco]

Hello,

I am studying certain techniques used in solving an old puzzle. In the next configuration, I understood the loop move (in my view is

Hidden Text: Show

(7=1385)r3468c3-(5)r2c3= r2c2-r5c2=(5)r5c8-(5=378)b9p458 Loop => many eliminations

Often I use Hodoku to double-check every step (mainly to check eliminations). Here I do not understand its output. Never liked Nice Loop Notation, but this does no seem to be the problem.

Code: Select all

.-------------------------.-----------------.------------------------.
| 1238    389    -12-3-89 | 6   78     4    |  5      -3789    137   |
| 7      *589    *5-89    | 3   1      2    |  489     489     6     |
| 4       6      B138     | 9   5      78   |  178     2       137   |
:-------------------------+-----------------+------------------------:
| 3568    3-578  B358     | 45  36789  3789 |  24679   1       257   |
| 9      *57      4       | 2   67     1    |  3      *567     8     |
| 13568   2      B1358    | 45  36789  3789 |  4679    4-5679  57    |
:-------------------------+-----------------+------------------------:
| 23      1       2-379   | 8   39     5    |  267    -367     4     |
| 358     4      B3578    | 1   2      6    | A78     A3578    9     |
| 2358    3-589   6       | 7   4      39   |  12-8   A358     12-35 |
'-------------------------'-----------------'------------------------'

Grouped Continuous Nice Loop:
1/3/5/8 9= r2c3 =5= r2c2 -5- r5c2 =5= r5c8 -5- ALS:r8c78,r9c8 -7- ALS:r3468c3 =9= r2c3 =5 => many elimination.

I have indicated in bold the part that I don't understand (among other things that 9 is not even part of the ALS and how come 9 and 5 are strongly linked in r3c3).

Thank you in advance.
Regards,

[SpAce]

Hi jco,

grid: Show

Code: Select all

.-------------------------.-----------------.------------------------.
| 1238    389    -12-3-89 | 6   78     4    |  5      -3789    137   |
| 7      *589    *5-89    | 3   1      2    |  489     489     6     |
| 4       6      B138     | 9   5      78   |  178     2       137   |
:-------------------------+-----------------+------------------------:
| 3568    3-578  B358     | 45  36789  3789 |  24679   1       257   |
| 9      *57      4       | 2   67     1    |  3      *567     8     |
| 13568   2      B1358    | 45  36789  3789 |  4679    4-5679  57    |
:-------------------------+-----------------+------------------------:
| 23      1       2-379   | 8   39     5    |  267    -367     4     |
| 358     4      B3578    | 1   2      6    | A78     A3578    9     |
| 2358    3-589   6       | 7   4      39   |  12-8   A358     12-35 |
'-------------------------'-----------------'------------------------'

Grouped Continuous Nice Loop:
1/3/5/8 9= r2c3 =5= r2c2 -5- r5c2 =5= r5c8 -5- ALS:r8c78,r9c8 -7- ALS:r3468c3 =9= r2c3 =5 => many elimination.

I have indicated in bold the part that I don't understand (among other things that 9 is not even part of the ALS and how come 9 and 5 are strongly linked in r3c3).

You're right. It doesn't make any sense. I almost never read Hodoku's output anyway because it's so unreadable (and sometimes faulty, like here). I just look at the pattern, and if need be, write my own notation of it. In this case I wrote:

Code: Select all

.-------------------------.-----------------.-------------------------.
| 1238    389     29-138  | 6   78     4    |  5       789-3   137    |
| 7      b589    a59-8    | 3   1      2    |  489     489     6      |
| 4       6      f138     | 9   5      78   |  178     2       137    |
:-------------------------+-----------------+-------------------------:
| 3568    378-5  f5'38    | 45  36789  3789 |  24679   1       257    |
| 9      c57      4       | 2   67     1    |  3      d567     8      |
| 13568   2      f5'138   | 45  36789  3789 |  4679    4679-5  57     |
:-------------------------+-----------------+-------------------------:
| 23      1       279-3   | 8   39     5    |  267     67-3     4     |
| 358     4      f5'38'7  | 1   2      6    | e7'8    e7'38'5   9     |
| 2358    389-5   6       | 7   4      39   |  12-8   e38'5     125-3 |
'-------------------------'-----------------'-------------------------'

(5)r2c3 = r2c2 - r5c2 = r5c8 - (5=38'7)b9p458 - (7=138'5)r3468c3 - loop => -12 elims


...which is equivalent to yours:

(7=1385)r3468c3-(5)r2c3= r2c2-r5c2=(5)r5c8-(5=378)b9p458 Loop => many eliminations

I just used a different starting point to match Hodoku's move as closely as possible. In any case, 9r2c3 plays no part.