How to Solve a Sudoku Faster
Sudoku puzzles test logic, intuition and patience and often even frustrate an avid solver. The different levels of Sudoku range from easy to diabolical, yet finishing any type of puzzle requires the same set of techniques. Although having a systematic way to solve a puzzle remains crucial, it often takes a little bit of practice to recognize and to master the techniques (often more for the harder levels of difficulty).
Other People Are Reading
Instructions
-
-
1
Identify the possible candidates, 1 to 9, in each empty cell. The possible candidates are numbers that have not appeared in the corresponding column, row or box. For example, a column with (1) (4) and (9) indicates that only 2, 3, 5, 6, 7, and 8 are the possible candidates for the other cells in that column. Always cross-check with every corresponding column, row or box for each cell in order to minimize the number of possible candidates.
-
2
Pencil in each cell where only one candidate appears (called Naked Singles) and eliminate it from the corresponding column, row and box.
-
-
3
Identify a candidate that appears more than two times in a column, row or box. Sometimes a cell may appear to have more than one possible candidate, but only one possible candidate belongs there (called Hidden Singles). For example, if you have (1 2) in two cells and (1 9) in another cell, then eliminate the 1 from the third cell as the 1 must belong to one of the other two cells.
-
4
Find where two cells contain two identical candidates, eliminate them from all other corresponding column, row or box (called Naked Doubles). For example, eliminate both 2 and 9 from all other corresponding cells when you already have (2 9) in two cells.
-
5
Observe where three cells have three identical candidates and eliminate them from all other corresponding column, row or box (called Naked Triples). For example, eliminate 1, 4 and 9 from all other corresponding cells when you have (1 4) (1 9) and (4 9).
-
6
Notice where four cells have four identical candidates, eliminate them from all other corresponding column, row or box (called Naked Quads). For example, eliminate 1, 3, 6 and 8 from all corresponding cells when you have (1 3) (1 3 6) (3 6 8) and (1 6 8).
-
7
Remember to pencil in any cell where only one candidate appears at any point in the game and to eliminate it from all corresponding cells. This crucial step helps to eliminate possible candidates and to solve the puzzle faster.
-
1
Tips & Warnings
It takes some time to familiarize yourself with the techniques, but having a systematic approach yields a faster way to solve Sudoku puzzles.
References
- Photo Credit Sudoku image by Claude Wangen from Fotolia.com
