2 1 6 7 4 1 3 9 2 6 3 5 1 8 9 4 7 3 5 5 9 3 7 2 5 1 8 4 21-01-2021.......hard 21-01-2021 www.daily-sudoku-puzzle.com

8 2 1 4 6 3 7 5 9 4 5 6 9 7 8 2 3 1 3 7 9 1 2 5 4 6 8 6 9 3 5 8 4 1 2 7 5 8 7 2 3 1 6 9 4 2 1 4 6 9 7 3 8 5 1 4 2 8 5 6 9 7 3 7 6 8 3 4 9 5 1 2 9 3 5 7 1 2 8 4 6

9=>(1,9) | 5=>(5,1) | 7=>(2,5) | 8=>(1,1) | 7=>(3,2) | 7=>(5,3) | 5=>(2,2) | 6=>(2,3) | 9=>(4,2) | 2=>(7,3) | 2=>(6,1) | 1=>(7,1) | 9=>(9,1) | 2=>(2,7) | 1=>(6,2) | 8=>(8,3) | 2=>(4,8) | 1=>(8,8) | 7=>(4,9) | 5=>(8,7) | 7=>(7,8) | 7=>(9,4) | 8=>(6,8) | 6=>(9,9) | 8=>(3,9) | 3=>(2,8) | 3=>(9,2) | 4=>(3,7) | 2=>(5,4) | 4=>(5,9) | 9=>(6,5) | 8=>(4,5) | 6=>(6,4) | 6=>(5,7) | 6=>(3,8) | 2=>(9,6) | 5=>(1,8) | 1=>(3,4) | 5=>(3,6) | 4=>(4,6) | 1=>(5,6) | 3=>(5,5) | 4=>(8,5) | 4=>(1,4) | 3=>(1,6) | 4=>(7,2) | 6=>(8,2) | 8=>(7,4) | 9=>(2,4) | 8=>(2,6) | 3=>(8,4) | 6=>(7,6) | 9=>(8,6) |