The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |38.|.6.|.79|
 |2..|8..|..4|
 |..9|2..|3..|
 |---+---+---|
 |...|...|93.|
 |8..|...|..1|
 |.24|...|...|
 |---+---+---|
 |..8|..6|4..|
 |1..|..4|..3|
 |46.|.3.|.15|
 *-----------*

38..6..792..8....4..92..3........93.8.......1.24........8..64..1....4..346..3..15


Play/Print this puzzle online

[Ngisa]

Code: Select all

+---------------------+--------------------+-------------------+
| 3       8       1   | 4      6       5   | 2      7       9  |
| 2       57      567 | 8      9       3   | 1      56      4  |
| 56      4       9   | 2      17      17  | 3      568     68 |
+---------------------+--------------------+-------------------+
|b567     1       56  |a57     4       8   | 9      3       2  |
| 8       59      3   | 6      27-5    279 | 57     4       1  |
|b579     2       4   | 3      17-5    179 | 57     68      68 |
+---------------------+--------------------+-------------------+
|b59      3       8   | 1     c25      6   | 4      29      7  |
| 1       579     257 | 7-5    8       4   | 6      29      3  |
| 4       6       27  | 9      3       27  | 8      1       5  |
+---------------------+--------------------+-------------------+


(5=7)r4c4 - (795)r467c1 = (5)r7c5 => - 5r8c4,r56c5; stte

Clement

[SpAce]

Code: Select all

.------------------.--------------------.--------------.
|   3     8    1   | 4    6      5      | 2    7    9  |
|   2     57   567 | 8    9      3      | 1    56   4  |
|   56    4    9   | 2    17+    17+    | 3    568  68 |
:------------------+--------------------+--------------:
|   567   1    56  | 57   4      8      | 9    3    2  |
|   8     59   3   | 6    57+2   279    | 57+  4    1  |
|   57-9  2    4   | 3    157+  a17[+9] | 57+  68   68 |
:------------------+--------------------+--------------:
| b(59)   3    8   | 1   b2(#5)  6      | 4    29   7  |
|   1     579  257 | 57   8      4      | 6    29   3  |
|   4     6    27  | 9    3      27     | 8    1    5  |
'------------------'--------------------'--------------'

MUG+2 (157)b256 using mixed +internal/#external

(9)r6c6 == (59)r7c51 => -9 r6c1; stte

...though that MUG complication doesn't gain much compared to this:

(9)r6c6 = (92)r5c65 - (2=59)r7c51 => -9 r6c1; stte

[SpAce]

(5=7)r4c4 - (795)r467c1 = (5)r7c5 => - 5r8c4,r56c5; stte

That weak link doesn't work as written. Easily fixed, though.

[Ngisa]

(5=7)r4c4 - (795)r467c1 = (5)r7c5 => - 5r8c4,r56c5; stte

That weak link doesn't work as written. Easily fixed, though.

Elaborate.

[SteveG48]

Code: Select all

 *--------------------------------------------------*
 | 3    8    1    | 4    6    5    | 2    7    9    |
 | 2    57   567  | 8    9    3    | 1    56   4    |
 | 56   4    9    | 2    17   17   | 3    568  68   |
 *----------------+----------------+----------------|
 | 567  1    56   | 57   4    8    | 9    3    2    |
 | 8   a59   3    | 6   a257  279  |a57   4    1    |
 | 57-9 2    4    | 3    157  179  | 57   68   68   |
 *----------------+----------------+----------------|
 |b59   3    8    | 1   b25   6    | 4    29   7    |
 | 1    57-9 257  | 57   8    4    | 6    29   3    |
 | 4    6    27   | 9    3    27   | 8    1    5    |
 *--------------------------------------------------*


(9=572)r5c257 - (2=59)r57c5 => -9 r6c1,r8c2 ; stte

[Sudtyro2]

Code: Select all

+---------------------+----------------+-------------+
|   3      8     1    | 4    6    5    | 2   7   9   |
|   2      57    567  | 8    9    3    | 1   56  4   |
|  b56#    4     9    | 2    17   17   | 3   568 68  |
+---------------------+----------------+-------------+
|   567*   1    a56#  | 57*  4    8    | 9   3   2   |
|   8     e9-5   3    | 6    257  279  | 57  4   1   |
|  a579#   2     4    | 3    157  179  | 57  68  68  |
+---------------------+----------------+-------------+
|  c59*    3     8    | 1    25*  6    | 4   29  7   |
|   1     d579   257  | 57*  8    4    | 6   29  3   |
|   4      6     27   | 9    3    27   | 8   1   5   |
+---------------------+----------------+-------------+

In 5s, a 5-link oddagon(*) with three guardians(#).
5b4p37 == r3c1 - (5=9)r7c1 - r8c2 = 9r5c2 => -5 r5c2; stte

SteveC

[SpAce]

Elaborate.

No. Outside of a military (or similar) environment I'm utterly incapable of responding to the imperative mood. At the very least, try with "please" next time. Besides, I haven't seen you appreciate the help you've received before. Seems that "thanks" is mostly missing from your vocabulary as well.

Therefore, if I bother to point out your mistakes, it's only to help those who actually want to learn to write Eureka correctly. I've seen little evidence that you do, and I'm fine with that. You're totally free to write your chains as you like and to ignore every piece of criticism they get.

However, if you do want to write compliant chains, then you should probably switch off the unappreciative and somewhat belligerent attitude you've shown in the past. It's a hindrance to your learning.

[blue]

(5=7)r4c4 - (795)r467c1 = (5)r7c5 => - 5r8c4,r56c5; stte

That weak link doesn't work as written. Easily fixed, though.

Elaborate.

Intresting situation.

I wonder if the reversal would slip by without notice:

(5)r7c5 = (597)r764c1 - (7=5)r4c4

[Ngisa]

Elaborate.

No. Outside of a military (or similar) environment I'm utterly incapable of responding to the imperative mood. At the very least, try with "please" next time. Besides, I haven't seen you appreciate the help you've received before. Seems that "thanks" is mostly missing from your vocabulary as well.

Therefore, if I bother to point out your mistakes, it's only to help those who actually want to learn to write Eureka correctly. I've seen little evidence that you do, and I'm fine with that. You're totally free to write your chains as you like and to ignore every piece of criticism they get.

However, if you do want to write compliant chains, then you should probably switch off the unappreciative and somewhat belligerent attitude you've shown in the past. It's a hindrance to your learning.

Well, I just wanted to shorten the chain:
(5=7)r4c4 - (7)r4c1 = (7-9)r6c1 = (9-5)r7c1 = (5)r7c5 =>....

[SpAce]

Intresting situation.

I wonder if the reversal would slip by without notice:

(5)r7c5 = (597)r764c1 - (7=5)r4c4

Not past me (probably) The mistake might be slightly harder to notice because the chain is more natural to read that way, but obviously it's still there because the reversal doesn't really change anything. In both cases the intended logic is easy to deduce by looking at the full chain and the grid, but as per AIC rules, every link must work independently and that doesn't happen here.

The strong link (5)r7c5 = (597)r764c1 is valid, but the (unordered) locked set (597)r764c1 doesn't imply a locked 7r4c1 (7 can be in r6c1 as well) which is required for the weak link with 7r4c4. Thus, even though we know how the digits will be distributed because of the preceding strong link, the weak link (597)r764c1 - (7)r4c3 is not valid when viewed in isolation. The dreaded comma (implying an ordered tuple) is needed:

(5)r7c5 = (5,9,7)r764c1 - (7=5)r4c3

Now the 7r4c1 is fixed, as it should be for the weak link to work. That works just as well in the original orientation:

(5=7)r4c3 - (7,9,5)r467c1 = (5)r7c5

In other words, now the weak link is between 7r4c3 and that particular distribution of those digits in those cells, which is valid and enough for our purposes. The weak link between 7r4c3 and the full unordered (579)r467c1 locked set is not valid, however, because 7r4c3 doesn't forbid the distribution (5,7,9)r467c1.

If nuances like that are hard to grasp, which I fully understand, I would strongly recommend sticking to the long form:

Well, I just wanted to shorten the chain:
(5=7)r4c4 - (7)r4c1 = (7-9)r6c1 = (9-5)r7c1 = (5)r7c5 =>....

That is fully correct, of course. It can also be shortened without resorting to the comma:

(5=7)r4c3 - (79)r46c1 = (95)r7c15 => ...

This would also work:

(5,7)r4c41 = (79-5)r67c1 = (5)r7c5 => ...

[Sudtyro2]

Well, I just wanted to shorten the chain:
(5=7)r4c4 - (7)r4c1 = [(7-9)r6c1 =(9-5)r7c1] = (5)r7c5 =>....

Hi Clement,
Nothing wrong with the full chain...but for a more compacted Eureka format why not write the bracketed section as [(79-5)r67c1] or [(7-95)r67c1]? Analogous to ALS, either term is simply an AHS (Almost Hidden Set).

SteveC

[eleven]

Response to SpAce:
sudoku police has spoken (again).
i very apppreciate, that we have one, though in more cases i symphathise with the opposite site
[edit:] let's say some cases

[Cenoman]

Code: Select all

 +--------------------+-------------------+------------------+
 |  3     8     1     |  4    6     5     |  2    7     9    |
 |  2    b57#   567*  |  8    9     3     |  1    56*   4    |
 |  56*   4     9     |  2    17    17    |  3    568*  68*  |
 +--------------------+-------------------+------------------+
 |  567*  1     56*   | c57#  4     8     |  9    3     2    |
 |  8    a59    3     |  6    257   279   |  57   4     1    |
 |  57-9  2     4     |  3    157   179   |  57   68*   68*  |
 +--------------------+-------------------+------------------+
 | f59    3     8     |  1   e25    6     |  4    29    7    |
 |  1     57-9  257   | d57   8     4     |  6    29    3    |
 |  4     6     27    |  9    3     27    |  8    1     5    |
 +--------------------+-------------------+------------------+

MUG (568)r2c38, r3c189, r4c13, r6c89 using externals (#)
(9=5)r5c2 - (5)r2c2==(5)r4c4 - r8c4 = r7c5 - (5=9)r7c1 => -9 r8c2, r6c1

[SpAce]

Response to SpAce:
sudoku police has spoken (again).
i very apppreciate, that we have one, though in more cases i symphathise with the opposite site
[edit:] let's say some cases

Thanks, eleven, for the almost-compliment Believe it or not, I sympathize with the opposite side as well. I've been there!! That's why I know full well that none of this is self-explanatory. Many nuances are in fact counterintuitive. That's what makes them interesting to me, actually.

Yet, I fully understand that not everyone wants to invest the same amount of effort into learning such details, and I really have no desire to be seen as a grammar police. I'm in a good position to help those who are interested, however, because I've probably fallen into most of the pitfalls myself. It's taken a lot of work and help from others (such as yourself) to climb out and learn to avoid them instinctively.