The New Sudoku Players' Forum

[ArkieTech]

Code: Select all

 *-----------*
 |3..|.1.|...|
 |...|..4|3.8|
 |..2|.8.|..1|
 |---+---+---|
 |...|8..|2.3|
 |1.8|.32|..6|
 |.3.|.71|.8.|
 |---+---+---|
 |.7.|1..|9..|
 |...|..7|...|
 |.13|45.|...|
 *-----------*


Play/Print this puzzle online

[Leren]

Code: Select all

*--------------------------------------------------------------------------------*
| 3       8      b79       | 2579    1     Cc5-9e     | 6       4       27       |
| 57     a59      1        | 279     6       4        | 3       279     8        |
| 46      46      2        | 79d     8       3        | 57      579c    1        |
|--------------------------+--------------------------+--------------------------|
| 567    A569     79       | 8       4      B59       | 2       1       3        |
| 1       459a    8        | 59      3       2        | 457     57b     6        |
| 2       3       45       | 6       7       1        | 45      8       9        |
|--------------------------+--------------------------+--------------------------|
| 45      7       6        | 1       2       8        | 9       3       45       |
| 8       2       45       | 3       9       7        | 1       6       45       |
| 9       1       3        | 4       5       6        | 8       27      27       |
*--------------------------------------------------------------------------------*

Kraken Column 2 Digit 5 :

5 r2c2 - 9 r2c2 = r1c3            - 9 r1c6;

5 r4c2 - r4c6 = r1c6              - 9 r1c6;

5 r5C2 - r5c8 = (5-9) r3c8 = r3c4 - 9 r1c6; => - 9 r1c6; stte

Leren

[SteveG48]

Code: Select all

 *-----------------------------------------------------------*
 | 3     8    a79    | 2579  1     59    | 6     4    f27    |
 | 57   b5-9   1     | 279   6     4     | 3    f279   8     |
 | 46    46    2     | 79    8     3     |f57    579   1     |
 *-------------------+-------------------+-------------------|
 | 567  c569   79    | 8     4     59    | 2     1     3     |
 | 1    c459   8     | 59    3     2     | 457   57    6     |
 | 2     3    d45    | 6     7     1     |e45    8     9     |
 *-------------------+-------------------+-------------------|
 | 45    7     6     | 1     2     8     | 9     3     45    |
 | 8     2     45    | 3     9     7     | 1     6     45    |
 | 9     1     3     | 4     5     6     | 8     27    27    |
 *-----------------------------------------------------------*


9r1c3 = (9-5)r2c2 = r45c2 - r6c3 = r6c7 - (5=279)b3p357 => -9 r2c2 ; stte

[Marty R.]

Code: Select all

+------------+-----------+------------+
| 3   8   79 | 2579 1 59 | 6   4   27 |
| 57  59  1  | 279  6 4  | 3   279 8  |
| 46  46  2  | 79   8 3  | 57  579 1  |
+------------+-----------+------------+
| 567 569 79 | 8    4 59 | 2   1   3  |
| 1   459 8  | 59   3 2  | 457 57  6  |
| 2   3   45 | 6    7 1  | 45  8   9  |
+------------+-----------+------------+
| 45  7   6  | 1    2 8  | 9   3   45 |
| 8   2   45 | 3    9 7  | 1   6   45 |
| 9   1   3  | 4    5 6  | 8   27  27 |
+------------+-----------+------------+


Play this puzzle online at the Daily Sudoku site

UR (57)r35c78, using externals
7r3c4=5r6c7
5r6c7-(5=79)r3c74-r5c4=r4c6-(9=7)r4c3-(7=95)b1p35
7r3c4-(7=5)r3c7-r56c7=r5c8-(5=94*)r5c42-[4=6*]r3c2-(4=5*)r6c3=> 95r42c2=> 5r2c2

Sorry about the notional mess. That 2nd line is a mess because it's notionally challenging. It can be seen that the asterisked 5&6 set r4c2=9 and r2c2=5

[JC Van Hay]

Code: Select all

+--------------------+---------------+--------------+
| 3      8      7(9) | 2579  1  (59) | 6    4    27 |
| 7(5)   (59)   1    | 279   6  4    | 3    279  8  |
| 46     46     2    | 79    8  3    | 57   579  1  |
+--------------------+---------------+--------------+
| 67(5)  69(5)  79   | 8     4  9(5) | 2    1    3  |
| 1      459    8    | 59    3  2    | 457  57   6  |
| 2      3      45   | 6     7  1    | 45   8    9  |
+--------------------+---------------+--------------+
| 4-5    7      6    | 1     2  8    | 9    3    45 |
| 8      2      45   | 3     9  7    | 1    6    45 |
| 9      1      3    | 4     5  6    | 8    27   27 |
+--------------------+---------------+--------------+
5r7c1
5r2c1 5r2c2
      9r2c2 9r1c3
5r4c1 5r4c2       5r4c6
            9r1c6 5r1c6


or [XWing(5r24c12)=5r4c6-(5=9)r1c6-9r1c3=(9-5)r2c2=5r2c1]-5r7c1; stte

[hughwill69]

Being new here I hope I'm not making any faux pas! If so sorry:

Code: Select all

+------------+-----------+------------+
| 3   8   79 | 2579 1 59 | 6   4   27 |
| 57  59  1  | 279  6 4  | 3   279 8  |
| 46  46  2  | 79   8 3  | 57  579 1  |
+------------+-----------+------------+
| 567 569 79 | 8    4 59 | 2   1   3  |
| 1   459 8  | 59   3 2  | 457 57  6  |
| 2   3   45 | 6    7 1  | 45  8   9  |
+------------+-----------+------------+
| 45  7   6  | 1    2 8  | 9   3   45 |
| 8   2   45 | 3    9 7  | 1   6   45 |
| 9   1   3  | 4    5 6  | 8   27  27 |
+------------+-----------+------------+


Play this puzzle online at the Daily Sudoku site

X wing on 9 r14c36 then 56-4 XYwing pivot r4c2 r3c2<>6

[ArkieTech]

Code: Select all

 *-----------------------------------------------------------*
 | 3     8    a79    | 257-9 1     5-9   | 6     4     27    |
 |a57    59    1     | 279   6     4     | 3     279   8     |
 | 46    46    2     |f79    8     3     |f57    579   1     |
 |-------------------+-------------------+-------------------|
 | 567   569   79    | 8     4     59    | 2     1     3     |
 | 1     459   8     | 59    3     2     | 457   57    6     |
 | 2     3    d45    | 6     7     1     |e45    8     9     |
 |-------------------+-------------------+-------------------|
 |b45    7     6     | 1     2     8     | 9     3     45    |
 | 8     2    c45    | 3     9     7     | 1     6     45    |
 | 9     1     3     | 4     5     6     | 8     27    27    |
 *-----------------------------------------------------------*
[(9=5)b1p34-r7c1=r8c3-r6c3=r6c7-(5=9)r3c47]-9r1c46; ste



[eleven]

Being new here I hope I'm not making any faux pas!
...
X wing on 9 r14c36 then 56-4 XYwing pivot r4c2 r3c2<>6

You are welcome.

Your solution is clearly easier than the others, and it is what manual players normally would try to find.
People here have an additional goal to find a "one-step" solution, i.e. only one advanced move, which breaks the puzzles into pieces, so that only singles (stte - singles to the end) or basic moves (locked candidates, pairs, triples, quads) are needed then to solve it completely.
That's the reason why these rather complex constructs are used for a relatively easy puzzle.

[eleven]

UR (57)r35c78, using externals
7r3c4=5r6c7
5r6c7-(5=79)r3c74-r5c4=r4c6-(9=7)r4c3-(7=95)b1p35
7r3c4-(7=5)r3c7-r56c7=r5c8-(5=94*)r5c42-[4=6*]r3c2-(4=5*)r6c3=> 95r42c2=> 5r2c2

Sorry about the notional mess. That 2nd line is a mess because it's notionally challenging. It can be seen that the asterisked 5&6 set r4c2=9 and r2c2=5

Code: Select all

+--------------+------------+---------------+
| 3     8   79 | #2579 1  59 |  6    4   #27 |
| 57   g59  1  | #279  6  4  |  3   #279  8  |
| 46    46  2  | a79   8  3  | b57   579  1  |
+--------------+-------------+---------------+
| 567  f569 79 |  8    4  59 |  2    1    3  |
| 1   fd459 8  | d59   3  2  | c457 d57   6  |
| 2     3  e45 |  6    7  1  | c45   8    9  |
+--------------+-------------+---------------+
| 45    7   6  |  1    2  8  |  9    3    45 |
| 8     2   45 |  3    9  7  |  1    6    45 |
| 9     1   3  |  4    5  6  |  8   #27  #27 |
+--------------+------------+---------------+

For your net from 7r3c4 to 5r2c2 there is also a linear way:
7r3c4-(7=5)r3c7-r56c7=r5c8-(5=49)r5c24-(4=5)r6c3-r45c2=5r2c2

7r3c4 is also external of the 27 DP, the second one being 9r2c8, which directly leads to 5r2c2 too.

[SteveG48]

Code: Select all

+------------+-----------+------------+
| 3   8   79 | 2579 1 59 | 6   4   27 |
| 57  59  1  | 279  6 4  | 3   279 8  |
| 46  46  2  | 79   8 3  | 57  579 1  |
+------------+-----------+------------+
| 567 569 79 | 8    4 59 | 2   1   3  |
| 1   459 8  | 59   3 2  | 457 57  6  |
| 2   3   45 | 6    7 1  | 45  8   9  |
+------------+-----------+------------+
| 45  7   6  | 1    2 8  | 9   3   45 |
| 8   2   45 | 3    9 7  | 1   6   45 |
| 9   1   3  | 4    5 6  | 8   27  27 |
+------------+-----------+------------+


Play this puzzle online at the Daily Sudoku site

UR (57)r35c78, using externals
7r3c4=5r6c7
5r6c7-(5=79)r3c74-r5c4=r4c6-(9=7)r4c3-(7=95)b1p35
7r3c4-(7=5)r3c7-r56c7=r5c8-(5=94*)r5c42-[4=6*]r3c2-(4=5*)r6c3=> 95r42c2=> 5r2c2

Sorry about the notional mess. That 2nd line is a mess because it's notionally challenging. It can be seen that the asterisked 5&6 set r4c2=9 and r2c2=5

Marty, I like your overall solution, but I don't understand where the UR is needed.
You're first chain could as easily have been: (7=9)r3c4 - r5c4 = r4c6 - r4c3 = 9r1c3.

Now each of your chains results in a 9 in either r1c3 or r4c2, giving your result.

In fact, I would turn around your first chain and write:

9r1c3 = r4c3 - r4c6 = r5c4 - (9=7)r4c4 - (7=5)r3c7 - r56c7 = r5c8 - (5=49)r5c24 - 4r2c2|4r6c3 = 6r2c2&5r6c3 - (56=9)r4c2 => -9 r2c2

[bat999]

Code: Select all

.-----------------.---------------.----------------.
|  3     8    d79 |  2579  1  d59 |  6     4    27 |
| c57    59    1  |  279   6   4  |  3     279  8  |
| b46   a46    2  |  79    8   3  |  57    579  1  |
:-----------------+---------------+----------------:
|  567   569   79 |  8     4  e59 |  2     1    3  |
|  1     59-4  8  | f59    3   2  | f457  f57   6  |
|  2     3     45 |  6     7   1  |  45    8    9  |
:-----------------+---------------+----------------:
| c45    7     6  |  1     2   8  |  9     3    45 |
|  8     2     45 |  3     9   7  |  1     6    45 |
|  9     1     3  |  4     5   6  |  8     27   27 |
'-----------------'---------------'----------------'

(4)r3c2 = r3c1 - (4=7)r27c1 - (7=5)r1c36 - (5=9)r4c6 - (9=4)r5c478 => -4 r5c2; stte

[eleven]

Marty, I like your overall solution, but I don't understand where the UR is needed.

You are pretty right, that the UR is not needed. Instead of the UR link 7r3c4=5r6c7 (or 7r3c4=9r2c9) here the direct link (7=9)r3c4 also works.
But the UR links jump into the eye, so why not start with them?

Why should i try (7=9)r3c4 and not one of the other 20 bivalue or 31 bilocation links (if counted right) ? If i would work this way, going from one 2-way link to the next, until i find something, i would leave solving to the programs.

[SteveG48]

Marty, I like your overall solution, but I don't understand where the UR is needed.

You are pretty right, that the UR is not needed. Instead of the UR link 7r3c4=5r6c7 (or 7r3c4=9r2c9) here the direct link (7=9)r3c4 also works.
But the UR links jump into the eye, so why not start with them?

Why should i try (7=9)r3c4 and not one of the other 20 bivalue or 31 bilocation links (if counted right) ? If i would work this way, going from one 2-way link to the next, until i find something, i would leave solving to the programs.

Good point, and I did like the business with 4r5c2. I should have just left it alone.

[pjb]

Code: Select all

 3       8       79     | 2579   1      59     | 6      4      27     
 57     a59      1      | 279    6      4      | 3     b279    8     
 46      46      2      | 79     8      3      |d57    c579    1     
------------------------+----------------------+---------------------
 567     69-5    79     | 8      4      59     | 2      1      3     
 1       49-5    8      | 59     3      2      | 457    57     6     
 2       3      f45     | 6      7      1      |e45     8      9     
------------------------+----------------------+---------------------
 45      7       6      | 1      2      8      | 9      3      45     
 8       2       45     | 3      9      7      | 1      6      45     
 9       1       3      | 4      5      6      | 8      27     27     


(5=9)r2c2 - r2c8 = (9-5)r3c8 = r3c7 - (5=4)r6c7 - (4=5)r6c3 => -5 r45c2; stte

Phil

[Marty R.]

Marty, I like your overall solution, but I don't understand where the UR is needed.
You're first chain could as easily have been: (7=9)r3c4 - r5c4 = r4c6 - r4c3 = 9r1c3.

Now each of your chains results in a 9 in either r1c3 or r4c2, giving your result.

In fact, I would turn around your first chain and write:

9r1c3 = r4c3 - r4c6 = r5c4 - (9=7)r4c4 - (7=5)r3c7 - r56c7 = r5c8 - (5=49)r5c24 - 4r2c2|4r6c3 = 6r2c2&5r6c3 - (56=9)r4c2 => -9 r2c2

Steve I have no doubt that you're correct about the UR not being needed. I was not claiming that it was. The way I play, being terrible at chains, I avoid situations where I have to find a chain, because too often I end up in what I call "chain purgatory." So I always look for a pattern-based move. I checked the UR and used it because it can solve the puzzle. I used two chains, one for each DP killer because I was unable to find a single chain that worked. I frequently use URs or DPs. They are a treasure trove or mother lode for non-chain solutions.