Weekly Extreme Sudoku Competition for Jan 20 to Jan 26

Number 644, Extreme
by Crosswords Ltd. December 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
      1 4   9    
      6   5     4
              3 5
5 8           9  
      2   6      
  4           1 2
8 6              
1     7       8  
    4   6 3