
Rules:
- Grid: A 9x9 grid divided into 3x3 subgrids called "regions" or "boxes."
- Digits: Fill the grid so that each column, each row, and each of the nine 3x3 subgrids contain all of the digits from 1 to 9.
Basic Strategies:
Single Possibility (or Naked Single):
- Look for cells where only one number can fit based on existing numbers in the row, column, and box.
Elimination (or Candidate Elimination):
- Identify numbers that can only go in one place in a row, column, or box due to existing numbers.
Subsets (or Naked Pairs/Triples):
- Identify sets of cells within a row, column, or box that can only contain the same two or three numbers, eliminating those numbers as candidates from other cells in the same unit.
Hidden Singles:
- Search for cells that are the only ones in a row, column, or box that can contain a specific number.
Step-by-Step Solving:
Scan the Grid: Start by scanning the grid for obvious numbers that can only go in one cell.
Use Elimination: Look for rows, columns, or boxes where a number can only go in one place due to other numbers already present.
Apply Subsets: Identify and eliminate candidate numbers in rows, columns, or boxes where specific numbers can only fit in certain cells.
Repeat and Check: Continue scanning and applying strategies until you fill the grid.
Tips:
- Practice: Regular practice improves pattern recognition and speed.
- Patience: Sudoku requires logical thinking and may take time to master.
By combining these strategies and practicing regularly, you'll improve your ability to solve Sudoku puzzles efficiently.