What is the easiest way to solve a hard Sudoku puzzle?

What is the easiest way to solve a hard Sudoku puzzle?
How to Solve Hard Sudoku Puzzles

1 Use a pencil.
2 Note potential candidates in open squares.
3 Scan the board to process the puzzle.
4 Start with the obvious singles.
5 Revisit your candidates after you solve singles.
6 Identify naked or hidden pairs.
7 Move on to triples and quads.

How to Solve Hard Sudoku Puzzles
  1. 1 Use a pencil.
  2. 2 Note potential candidates in open squares.
  3. 3 Scan the board to process the puzzle.
  4. 4 Start with the obvious singles.
  5. 5 Revisit your candidates after you solve singles.
  6. 6 Identify naked or hidden pairs.
  7. 7 Move on to triples and quads.