Weekly Extreme Sudoku Competition for Dec 9 to Dec 15

Number 638, Extreme
by Crosswords Ltd. February puzzle packs Now Out!. Thanks for supporting our site.
Future Puzzle - will be submitted on the relevant day
1 2 3 4 5 6 7 8 9
A
B
C
D
E
F
G
H
J
8     2   3     6
        5     7  
  6     1       3
3             6  
    1   2   5    
  4           3 9
4       8     1  
  7     3        
5     9         2