https://www.sudoku-solutions.com/
chuck20211006-001
这个难度是easy，但是需要用到两次pointing pair和一次naked pair。
Step 1: Pointing Pair in cells ( A1 , C1 )
These cells are the only cells in column 1 with the candidate value 6. The candidate must be in one of these cells and can be removed from other cells in box 1.
Actions:
Candidates 6 removed from cells ( C2 )
Step 2: Pointing Pair in cells ( D6 , F6 )
These cells are the only cells in column 6 with the candidate value 8. The candidate must be in one of these cells and can be removed from other cells in box 5.
Actions:
Candidates 8 removed from cells ( D5 )
Step 3: Naked Pair in cells ( D3 , D9 )
Only these cells can have the candidate values 3,8
Actions:
Candidates 3,8 removed from cells ( D4, D6 )
Step 4: Hidden Single in cell ( F6 )
The cell is the only cell in column 6 with the candidate value 8
Actions:
Cell solved with the value 8.
Candidate 8 removed from cells ( F2 )
Candidate 8 removed from cells ( F2 )