The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |9..|..8|.6.|
 |..1|7..|5..|
 |.2.|.4.|..9|
 |---+---+---|
 |.8.|...|.4.|
 |..2|.1.|..3|
 |3..|...|6..|
 |---+---+---|
 |.3.|..1|8..|
 |4..|6..|..7|
 |..5|.7.|.9.|
 *-----------*


Play/Print this puzzle online

[SCLT]

Beautiful!

Code: Select all

*------------------------*---------------------------*-------------------------*
|  9      457     347    |  1235    235     8        |  12347   6       124    |
|  6-8    46      1      |  7       2369    2369     |  5       238     248    |
|  5678*  2       3678*  |  135     4       356      |  137     1378*   9      |
*------------------------+---------------------------+-------------------------*
|  1567   8       679    |  2359    23569   235679   |  1279    4       125    |
|  567    45679   2      |  4589*   1       45679    |  79      578*    3      |
|  3      14579   479    |  24589   2589    24579    |  6       12578   1258   |
*------------------------+---------------------------+-------------------------*
|  267    3       679    |  2459     259     1       |  8       25      2456   |
|  4      19      89     |  6        23589   2359    |  123     1235    7      |
|  1268*  16      5      |  2348*    7       234     |  1234    9       1246   |
*------------------------*---------------------------*-------------------------*


Finned swordfish: 8 r359 c148 fr3c3 => -8 r2c1 ; stte

[SpAce]

Code: Select all

.---------------------.----------------------.---------------------.
| 9     457    347    | 1235   235    8      | 12347  6       124  |
| 6-8   46     1      | 7      2369   2369   | 5      238    f24(8)|
| 5678  2     a367(8) | 135    4      356    | 137    137-8   9    |
:---------------------+----------------------+---------------------:
| 1567  8      679    | 2359   23569  235679 | 1279   4       125  |
| 567   45679  2      | 4589   1      45679  | 79     578     3    |
| 3     14579  479    | 24589 d2589   24579  | 6      12578  e1258 |
:---------------------+----------------------+---------------------:
| 267   3      679    | 2459   259    1      | 8      25      2456 |
| 4     19    b89     | 6     c23589  2359   | 123    1235    7    |
| 1268  16     5      | 2348   7      234    | 1234   9       1246 |
'---------------------'----------------------'---------------------'

(8)r3c3 = r8c3 - r8c5 = r6c5 - r6c9 = (8)r2c9 => - r2c1, r3c8; stte

Added: I guess those chain nodes could be seen like this as well:

Code: Select all

.-------------------.----------------------.--------------------.
| 9     457    347  | 1235   235    8      | 12347  6      124  |
| 68    46     1    | 7      2369   2369   | 5      238   #248  |
| 5678  2     *3678 | 135    4      356    | 137    137-8 *9    |
:-------------------+----------------------+--------------------:
| 1567  8      679  | 2359   23569  235679 | 1279   4      125  |
| 567   45679  2    | 4589   1      45679  | 79     578    3    |
| 3     14579  479  | 24589 *2589   24579  | 6      12578 *1258 |
:-------------------+----------------------+--------------------:
| 267   3      679  | 2459   259    1      | 8      25     2456 |
| 4     19    *89   | 6     *23589  2359   | 123    1235   7    |
| 1268  16     5    | 2348   7      234    | 1234   9      1246 |
'-------------------'----------------------'--------------------'

Sashimi Swordfish (8)c359/r369 f:r2c9 => -8 r3c8; lcte

[Cenoman]

Code: Select all

 +------------------------+---------------------------+-------------------------+
 |  9      457     347    |  1235    235     8        |  12347   6       124    |
 | a68     46      1      |  7      b2369*   2369     |  5       238     248    |
 |  5678   2      b3678*  |  135     4       356      |  137     1378    9      |
 +------------------------+---------------------------+-------------------------+
 |  1567   8      b679*   |  2359   b23569*  235679   |  1279    4       125    |
 |  567    45679   2      |  4589    1       45679    |  79      578     3      |
 |  3      14579   479    |  24589   2589    24579    |  6       12578   1258   |
 +------------------------+---------------------------+-------------------------+
 | d267    3      c679    |  2459    259     1        |  8       25      2456   |
 |  4      19      89     |  6       23589   2359     |  123     1235    7      |
 | d126-8  16      5      |  2348    7       234      |  1234    9       1246   |
 +------------------------+---------------------------+-------------------------+

Almost skyscraper (6)r3c3=r4c3-r4c5=r2c5 + rfr7c3
(8=6)r2c1 - [(6)r3c3*=r4c3-r4c5=r2c5] = (6-7)r7c3 = (72)r79c1 => -8 r9c1; ste

[SpAce]

Almost skyscraper (6)r3c3=r4c3-r4c5=r2c5 + rfr7c3
(8=6)r2c1 - [(6)r3c3*=r4c3-r4c5=r2c5] = (6-7)r7c3 = (72)r79c1 => -8 r9c1; ste

Beautiful! Wish I could spot those myself more frequently. What does the * denote? It looks like a memory marker but this chain doesn't need those. Also, while the chain is perfectly valid, I might personally find the logic easier to see if it were reversed, either as is or something like this:

(2)r9c1 = (27-6)r7c13 = Skyscraper[(6)r3c3=r4c3-r4c5=(6)r2c5] - (6=8)r2c1 => -8 r9c1

Somehow it feels more natural to enter a complex node with a strong link and leave it with a weak link than the other way around, even though both of course work. A matter of taste, nothing else -- my brain just needs to process the other option a bit more. Then again, it's good to get used to things that don't feel natural at first (that's why I'm not suggesting it needs to be changed at all).

[Cenoman]

What does the * denote?

In my chains embedding an almost-pattern, the * indicates the candidates which the one additional to the pattern (the "fin") is strongly linked to;

[SpAce]

In my chains embedding an almost-pattern, the * indicates the candidates which the one additional to the pattern (the "fin") is strongly linked to;

Thanks, Cenoman! I don't quite understand that explanation, though. Why should we care about any external links of individual candidates within the pattern? Isn't it easier to just think that the whole pattern is strongly linked to the "fin" (and weakly linked to its PEs)? How is 6r3c3 strongly linked to 6r7c3 here anyway?

[Cenoman]

Hi SpAce,
The concern is the use of square brackets [...] in chains.
A square bracket as any other node in a chain is surrounded with a strong link and a weak link (alternance in well named AICs) But what in the brackets is in a weak link and what is in a strong link ? By convention each extreme node inside the brackets is in a weak link with a potential elimination. The strong link branches somewhere inside on two nodes, already in a strong link themselves. You can leave the reader guess which nodes are addressed or try to help.
In the present example, (6)r3c3=r4c3 is not a native strong link in the PM. The 3-SIS (6)r3c3=r4c3=r7c3 is native.

Or you can say

the whole pattern is strongly linked to the "fin" and weakly linked to its PEs

. That is also correct to me.

Just a matter of taste, whether you would like to explain how the whole pattern is strongly linked to the "fin" or you prefer being terse.

[SpAce]

In the present example, (6)r3c3=r4c3 is not a native strong link in the PM. The 3-SIS (6)r3c3=r4c3=r7c3 is native.

Thanks again! I think I get your point now. So you want to specify the induced strong link (2-SIS) inside chain node? That's not a bad idea. However, your placement of the marker managed to confuse me, because it was next to r3c3 only, making it look like a memory marker. I think it should really mark the link itself. How about:

[(6)r3c3=*=r4c3-r4c5=(6)r2c5]

I think I would have been able to deduce its purpose more easily from something like that.