Basic Sudoku Solving Techniques
Master fundamental techniques for efficient solving
Naked Single
BeginnerThe most basic technique where a cell can only contain one possible number.
How to Use
- 1.Check the row, column, and box of the cell
- 2.Eliminate numbers already used
- 3.If only one number remains, it's confirmed
Example: If a row has 1,2,3,4,5,6,7,8 and the column lacks 9, the cell must be 9
Hidden Single
Beginner-IntermediateA technique where a number can only go in one cell within a row, column, or box.
How to Use
- 1.Focus on one row (or column/box)
- 2.Find missing numbers
- 3.If a number can only go in one place, confirm it
Example: If number 7 can only go in one cell in a row, place 7 there
Box Line Reduction
IntermediateWhen candidates for a number in a box are limited to one row or column, eliminate that number from other boxes in that line.
How to Use
- 1.Check candidate positions for a number in a box
- 2.See if candidates are limited to one row or column
- 3.Eliminate that number from other boxes in that line
Example: If 3 can only be in the top row of a box, eliminate 3 from other boxes in that row
Pencil Marking
BeginnerThe fundamental technique of noting possible numbers in each cell and using elimination.
How to Use
- 1.Note candidate numbers in empty cells
- 2.Remove candidates affected by confirmed numbers
- 3.Confirm cells with only one candidate
Example: A cell starts with candidates 1,3,5,7 but eliminations leave only 3
Naked Pair
IntermediateWhen two cells in the same unit have the same two candidates, eliminate those numbers from other cells in that unit.
How to Use
- 1.Find cells with exactly two candidates in a unit
- 2.Look for pairs with the same two candidates
- 3.Eliminate those two numbers from other cells in the unit
Example: If two cells in a row both have candidates 2,7, eliminate 2 and 7 from other cells in that row