The New Sudoku Players' Forum

[PeetNeef]

Hey guys,

Another puzzle again. Tried something with UR's and other techniques, but I can't work it out..

I hope the notes are clear.

https://ibb.co/C9fDjLb

[Hajime]

Code: Select all

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

8..6...125....49......5..7.7.9..53.............32..6.5.6..2......15....847...1..9

As far as I can see, all your cell solutions are correct.
Situation:

Code: Select all

                                               
+----------+------------------+--------------+ 
| 8  349 47|   6     379   379|  5    1    2 | 
| 5  123 27| 1378   1378    4 |  9   38    6 | 
|39 1349  6| 1389     5     2 | 48    7   34 | 
+----------+------------------+--------------+ 
| 7  248  9|  148     6     5 |  3   248  14 | 
| 6   5  24|134789 134789 3789|1478 2489  147| 
| 1  48   3|   2    4789   789|  6   489   5 | 
+----------+------------------+--------------+ 
|39   6   8| 3479     2    379| 147   5  1347| 
| 2  39   1|   5    3479    6 | 47   34    8 | 
| 4   7   5|  38     38     1 |  2    6    9 | 
+--------------------------------------------+

First some Naked/Hidden Pairs and Pointing/Claiming is needed.
NakedPair (38)b8e78 => (-3)r7c4 (-3)r7c6 (-3)r8c5
Pointing, Claiming | (4)r1,b1 => (-4)r3c2 | (7)b6,r5 => (-7)r5c4 (-7)r5c5 (-7)r5c6 | (8)c6,b5 => (-8)r4c4 (-8)r5c4 (-8)r5c5 (-8)r6c5
NakedPair (14)r4c49 => (-4)r4c2 (-4)r4c8

What next is needed now is a XY-wing, 3 cells involved on digit 4
(4)(4=8)r3c7-(8=3)r2c8-(3=4)r8c8 => (-4)r7c7 (-4)r8c7
meaning: if r3c7<>4 then r3c7=8, r2c8=3, r8c8=4.
So r3c7=4 or r8c8=4 !
All cells that 'see' r3c7 and r8c8 can eliminate candidate 4: (-4)r7c7 (-4)r8c7.
Singles to the end.