The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |.2.|93.|.16|
 |...|...|94.|
 |5..|...|...|
 |---+---+---|
 |..1|.9.|8.3|
 |.35|...|.9.|
 |...|...|7..|
 |---+---+---|
 |6..|5.4|...|
 |1..|.6.|...|
 |..9|..7|..2|
 *-----------*


Play/Print this puzzle online

[SteveG48]

Code: Select all

 *-----------------------------------------------------------------------------*
 | 47      2       47      | 9       3       8       | 5       1       6       |
 |a38      1       68-3    | 267     257     256     | 9       4       78      |
 | 5       9       68      | 1467    147     16      | 23      23      78      |
 *-------------------------+-------------------------+-------------------------|
 | 247     467     1       | 2467    9       256     | 8       256     3       |
 | 2478    3       5       | 124678  12478   126     | 246     9       14      |
 | 9       468     48      | 12468   12458   3       | 7       256     145     |
 *-------------------------+-------------------------+-------------------------|
 | 6      f78     f2378    | 5       128     4       | 13      378     9       |
 | 1      f4578   f23478   |d238     6       9       |e34      3578   e45      |
 |b48-3    458     9       |c138     18      7       | 1346    3568    2       |
 *-----------------------------------------------------------------------------*


Embedded chain:

(3)r2c1 = r9c1 - [(3)r9c4 = r8c4 - (3=45)r8c79 - (45=2378)r78c23] => -3 r2c3,r9c1 ; lclste

[daj95376]

Embedded chain:

(3)r2c1 = r9c1 - [(3)r9c4 = r8c4 - (3=45)r8c79 - (45=2378)r78c23] => -3 r2c3,r9c1 ; lclste

Steve, the embedded chain is sufficient.

_

[SteveG48]

Thanks, Danny. I knew that, but it was the longer chain that I saw first, so I left it.

[Leren]

Code: Select all

*---------------------------------------------------------------*
|b47    2    c47     | 9      3     8      | 5     1     6      |
|a38    1     368    | 267    257   256    | 9     4     78     |
| 5     9     68     | 1467   147   16     | 23    23    78     |
|--------------------+---------------------+--------------------|
| 247   467   1      | 2467   9     256    | 8     256   3      |
| 247-8 3     5      | 124678 12478 126    | 246   9     14     |
| 9     468  d48     | 12468  12458 3      | 7     256   145    |
|--------------------+---------------------+--------------------|
| 6     78    2378   | 5      128   4      | 13    378   9      |
| 1     4578  23478  | 238    6     9      | 34    3578  45     |
|a348   458   9      | 138    18    7      | 1346  3568  2      |
*---------------------------------------------------------------*

(8=4) r29c1 - r1c1= r1c3 - (4=8) r6c3 => - 8 r5c2; lclste

Leren

[Marty R.]

Code: Select all

+-----------------+------------------+---------------+
| 47   2    47    | 9      3     8   | 5    1    6   |
| 38   1    368   | 267    257   256 | 9    4    78  |
| 5    9    68    | 1467   147   16  | 23   23   78  |
+-----------------+------------------+---------------+
| 247  467  1     | 2467   9     256 | 8    256  3   |
| 2478 3    5     | 124678 12478 126 | 246  9    14  |
| 9    468  48    | 12468  12458 3   | 7    256  145 |
+-----------------+------------------+---------------+
| 6    78   2378  | 5      128   4   | 13   378  9   |
| 1    4578 23478 | 238    6     9   | 34   3578 45  |
| 348  458  9     | 138    18    7   | 1346 3568 2   |
+-----------------+------------------+---------------+


Play this puzzle online at the Daily Sudoku site

I solved the puzzle but telling you how I did it is a mess. Start with a Kite on 3 in b7. That says 3r2c1=3r7c78.

The notation is a bastardization, but I can't figure it out. Suffice it to say that the common outcome is r9c4=3.

3r2c1-(3468=7)r2361c3-(7=4)r1c1=>r9c1=8-(81=3)r9c54
3r7c78-(3=4)r8c7-(4=5)r8c9=>(168=3)r9c5784=>r9c4=3

[Marty R.]

Code: Select all

+-----------------+------------------+---------------+
| 47   2    47    | 9      3     8   | 5    1    6   |
| 38   1    368   | 267    257   256 | 9    4    78  |
| 5    9    68    | 1467   147   16  | 23   23   78  |
+-----------------+------------------+---------------+
| 247  467  1     | 2467   9     256 | 8    256  3   |
| 2478 3    5     | 124678 12478 126 | 246  9    14  |
| 9    468  48    | 12468  12458 3   | 7    256  145 |
+-----------------+------------------+---------------+
| 6    78   2378  | 5      128   4   | 13   378  9   |
| 1    4578 23478 | 238    6     9   | 34   3578 45  |
| 348  458  9     | 138    18    7   | 1346 3568 2   |
+-----------------+------------------+---------------+


Play this puzzle online at the Daily Sudoku site

I solved the puzzle but telling you how I did it is a mess. Start with a Kite on 3 in b7. That says 3r2c1=3r7c78.

The notation is a bastardization, but I can't figure it out. Suffice it to say that the common outcome is r9c4=3.

3r2c1-(3468=7)r2361c3-(7=4)r1c1=>r9c1=8-(81=3)r9c54
3r7c78-(3=4)r8c7-(4=5)r8c9=>(168=3)r9c5784=>r9c4=3

Slight improvement: remove the first line of notation. Once the second line =>r9c4=3, that can be used as a pincer with r2c1=>r9c1<>3.

[daj95376]

I solved the puzzle but telling you how I did it is a mess. Start with a Kite on 3 in b7. That says 3r2c1=3r7c78.

The notation is a bastardization, but I can't figure it out. Suffice it to say that the common outcome is r9c4=3.

3r2c1-(3468=7)r2361c3-(7=4)r1c1=>r9c1=8-(81=3)r9c54
3r7c78-(3=4)r8c7-(4=5)r8c9=>(168=3)r9c5784=>r9c4=3

Marty, forget the Kite (which it isn't) and just use the 3s in [r7].

Code: Select all

 +--------------------------------------------------------------------------------+
 |  47      2       47      |  9       3       8       |  5       1       6       |
 |  38      1       368     |  267     257     256     |  9       4       78      |
 |  5       9       68      |  1467    147     16      |  23      23      78      |
 |--------------------------+--------------------------+--------------------------|
 |  247     467     1       |  2467    9       256     |  8       256     3       |
 |  2478    3       5       |  124678  12478   126     |  246     9       14      |
 |  9       468     48      |  12468   12458   3       |  7       256     145     |
 |--------------------------+--------------------------+--------------------------|
 |  6       78      2378    |  5       128     4       |  13      378     9       |
 |  1       4578    23478   |  238     6       9       |  34      3578    45      |
 |  348     458     9       |  138     18      7       |  1346    3568    2       |
 +--------------------------------------------------------------------------------+
 # 101 eliminations remain

 (3*)r7c3  - (3=4678)r1236 - (7=4)r1c1 - (*34=8)r9c1 - (8=13)r9c45
      ||
 (3*)r7c78 - (3=4*)r8c7 - (4=5)r8c9 - (*345=16)r9c78 - (1=38)r9c45


FWIW: solution following assignment cascade to a DP contradiction:

Code: Select all

3r8c4 4r8c7 5r8c9 5r9c2 4r9c1 3r7c3; <78> DP r78c28 contradiction  =>  -3 r8c4


_

[Marty R.]

Danny,

Thank you, I was hoping you'd come to my rescue. What do the asterisks mean in the notation?

As to my using the term "Kite", it's hard for me not to use the term since that's what I learned very early in my Sudoku "career." That it was equivalent to a Skyscraper except that the "floor" (if that's a correct term) is a box rather than a line. If it's not a Kite, what is it? I think my initial premise of 3r2c1=3r7c78 is correct, isn't it? If it's not a Kite, what is it?

Once again, thanks for the reply.

[daj95376]

What do the asterisks mean in the notation?

As to my using the term "Kite", it's hard for me not to use the term since that's what I learned very early in my Sudoku "career." That it was equivalent to a Skyscraper except that the "floor" (if that's a correct term) is a box rather than a line. If it's not a Kite, what is it? I think my initial premise of 3r2c1=3r7c78 is correct, isn't it? If it's not a Kite, what is it?

Okay, here goes.

In a chain, the asterisks (*) represent "memory" use; i.e., embedded networking. When an asterisk follows one or more digits, then associated eliminations are remembered. When an asterisk appears before one or more digits, this is when remembered eliminations are applied. When the relationships become complex, additional symbols may be used to facilitate tracking remembered associations.

In exemplar grids (below), an asterisk represents an elimination in a cell.

Code: Select all

 typical example of an ungrouped 2-String Kite
 it's "named" after a specific turbot fish pattern
 +-----------------------+
 | / / X | / / / | / X / |
 | / . . | . . . | . . . |
 | X . . | . . . | . . . |
 |-------+-------+-------|
 | / . . | . . . | . . . |
 | X . . | . . . | . * . |
 | / . . | . . . | . . . |
 |-------+-------+-------|
 | / . . | . . . | . . . |
 | / . . | . . . | . . . |
 | / . . | . . . | . . . |
 +-----------------------+

 (node):  (1)    (2)    (3)    (4)          (5) 
 (X):     r1c8 = r1c3 - r3c1 = r5c1  =>  -X r5c8


Code: Select all

 typical example of a grouped 2-String Kite
 here, two of the nodes are grouped as a pair of cells
 +-----------------------+
 | / X X | / / / | / X / |
 | X . . | . . . | . . . |
 | X . . | . . . | . . . |
 |-------+-------+-------|
 | / . . | . . . | . . . |
 | X . . | . . . | . * . |
 | / . . | . . . | . . . |
 |-------+-------+-------|
 | / . . | . . . | . . . |
 | / . . | . . . | . . . |
 | / . . | . . . | . . . |
 +-----------------------+

 (node):  (1)    (2)     (3)     (4)          (5) 
 (X):     r1c8 = r1c23 - r23c1 = r5c1  =>  -X r5c8


What's important is to recognize that only pairs of cells in the box can be grouped ... and they must see a "tail" cell.

In your case, you found an X-Chain that forms a (logical) strong link between the endpoint cells:

Code: Select all

 +-----------------------+
 | / . . | . . . | . . . |
 | X . . | . . . | . . . |
 | / . . | . . . | . . . |
 |-------+-------+-------|
 | / . . | . . . | . . . |
 | / . . | . . . | . . . |
 | / . . | . . . | . . . |
 |-------+-------+-------|
 | / / X | / / / | X X / |
 | / . . | . . . | . . . |
 | X . . | . . . | . . . |
 +-----------------------+

 (endpoint):  (1)                  (2)
 (X):         r2c1 = r9c1 - r7c3 = r7c78  =>  nada


_