Weekly Extreme Sudoku Competition for Dec 24 to Dec 30

Number 588, Extreme
by Crosswords Ltd. November 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
  7           4  
2       1     3  
      6   7     5
  9             7
    8       1    
4             9 3
9     2   1      
  5     9     6  
  4       5   7