The New Sudoku Players' Forum

[Yogi]

9.24........6....1.........76.............54.......2..83..9...7....2..8......5...

Code: Select all

+---+---+---+
|9.2|4..|...|
|...|6..|..1|
|...|...|...|
+---+---+---+
|76.|...|...|
|...|...|54.|
|...|...|2..|
+---+---+---+
|83.|.9.|..7|
|...|.2.|.8.|
|...|..5|...|
+---+---+---+


[pjb]

Code: Select all

 9       5       2      | 4      3      1      | 7      6      8     
b34     c478     378    | 6      78     2      | 9      5      1     
 16      178     1678   | 5      78     9      | 4      3      2     
------------------------+----------------------+---------------------
 7       6       4      | 2      5      3      | 8      1      9     
a23     e89-2    389    | 7      1      68     | 5      4      36     
 5       18      138    | 9      4      68     | 2      7      36     
------------------------+----------------------+---------------------
 8       3       5      | 1      9      4      | 6      2      7     
 46     d49      69     | 3      2      7      | 1      8      5     
 1-2    f127     17     | 8      6      5      | 3      9      4     


(2=3)r5c1 - (3=4)r2c1 - (4)r2c2 = (4-9)r8c2 = (9-2)r5c2 = (2)r9c2 => -2 r5c2, r9c1; stte

Phil

[RSW]

Code: Select all

 +----------------+----------+--------+
 | 9     5   2    | 4  3  1  | 7 6 8  |
 | 3-4 a#478 378  | 6 #78 2  | 9 5 1  |
 |c16  b#178 1678 | 5 #78 9  | 4 3 2  |
 +----------------+----------+--------+
 | 7     6   4    | 2  5  3  | 8 1 9  |
 | 23    289 389  | 7  1  68 | 5 4 36 |
 | 5     18  138  | 9  4  68 | 2 7 36 |
 +----------------+----------+--------+
 | 8     3   5    | 1  9  4  | 6 2 7  |
 |d46    9-4 69   | 3  2  7  | 1 8 5  |
 | 12    127 17   | 8  6  5  | 3 9 4  |
 +----------------+----------+--------+


UR(78)r23c25
(4)r2c2 == (1)r3c2 - (1=6)r3c1 - (6=4)r8c1 => -4r2c1 -4r8c2; stte

[Cenoman]

For fun...

Code: Select all

 +--------------------+-----------------+-----------------+
 |  9    5     2      |  4    3    1    |  7    6    8    |
 |  34   478   378    |  6    78   2    |  9    5    1    |
 | b16  a178   1678   |  5    78   9    |  4    3    2    |
 +--------------------+-----------------+-----------------+
 |  7    6     4      |  2    5    3    |  8    1    9    |
 |  23  z28-9 C389*   |  7    1    68*  |  5    4    36*  |
 |  5   A18   B138*   |  9    4    68*  |  2    7    36*  |
 +--------------------+-----------------+-----------------+
 |  8    3     5      |  1    9    4    |  6    2    7    |
 | c46  c49    69     |  3    2    7    |  1    8    5    |
 |  12  y127   17     |  8    6    5    |  3    9    4    |
 +--------------------+-----------------+-----------------+

Kraken column (1)r369c2 using DP (368)r56c369 internals:
(1)r3c2 - (1=6)r3c1 - (6=49)r8c12
(1)r6c2 - (1)r6c3 =DP= (9)r5c3
(1-2)r9c2 = (2)r5c2
=> -9 r5c2; ste

[Yogi]

Thanx. I'm impressed by all solutions, but particularly RSW’s effort. Never seen this term == before, but I can understand what it means:
Because of the noted UR, there is a true or implied Strong Link between the 4 in r2c2 and the 1 in r3c2. If r2c2 is NOT 4, then r3c2 is 1, and the AIC continues normally from there to prove that when r2c2 is not 4 then r8c1 IS 4 and vice versa. This deletes 4 from the cells that can see them both and the puzzle is solved. Great!

[Cenoman]

Never seen this term == before, but I can understand what it means:
Because of the noted UR, there is a true or implied Strong Link ...

I've been using this symbol ==, or sometimes =UR= instead, for years, exactly with the meaning you mention (i.e. a strong link derived from a deadly pattern). I have learnt it from JC Van Hay, but I don't know if he was the inventor...

[RSW]

I learned it from Cenoman.