Overview of Sudoku Strategies
Easy• ~2 min read
A tour of core ideas: fill what is certain, eliminate what is impossible, and progress step-by-step.
Sudoku Techniques Guide
Learn Sudoku in plain language. These articles use gentle, step-by-step explanations with small examples so students and puzzle enthusiasts can build confidence.
Techniques
Crosshatching
Easy• ~2 min readA scanning technique where you focus on one number at a time and determine where it must go within each 3x3 box by eliminating positions using rows and columns that already contain that number.
Last Free Cell
Easy• ~2 min readIf eight cells in a row, column, or box are filled, the ninth cell can only contain the missing digit.
Naked Single
Easy• ~2 min readA cell that can only contain one possible digit after eliminating all numbers already present in its row, column, and box.
Hidden Single
Easy• ~2 min readA digit that can only be placed in one specific cell within a row, column, or box, even though other digits might also be possible in that cell.
Naked Pair
Medium• ~2 min readTwo cells in the same row, column, or box that can only contain the same two digits, allowing you to eliminate those digits from other cells in the same unit.
Pointing Pair
Medium• ~2 min readWhen all possible positions for a digit in a box are in the same row or column, you can eliminate that digit from the rest of that row or column.
Box/Line Reduction
Medium• ~2 min readWhen all possible positions for a digit in a row or column are within the same box, you can eliminate that digit from the rest of that box.
Naked Triple
Hard• ~2 min readThree cells in the same row, column, or box that can only contain the same three digits, allowing elimination of those digits from other cells in the same unit.
X-Wing
Expert• ~2 min readA pattern where a digit appears in exactly two cells in two different rows, and these cells form a rectangle, allowing elimination of the digit from the affected columns.
Y-Wing (XY-Wing)
Expert• ~2 min readA three-cell pattern where a pivot cell shares a unit with two pincer cells, enabling elimination of a common candidate from cells that see both pincers.
Swordfish
Expert• ~2 min readAn extension of X-Wing across three rows and three columns, where a digit can be eliminated from three entire columns based on a rectangular pattern.
Note Validation (Auto-Fix)
Auto-Fix• ~2 min readAn automated process to correct pencil marks that are logically impossible, helping you maintain accurate candidates.
Bruteforce (Last Resort)
Last Resort• ~2 min readA trial-and-error method used when logical techniques are exhausted. You guess a candidate, follow the consequences, and backtrack if a contradiction arises.
Elimination Method
Easy• ~2 min readThe foundational Sudoku solving principle: systematically remove impossible candidates from cells based on row, column, and box constraints until the solution emerges.
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Practice Techniques on Paper
Download free printable Sudoku puzzles to practice these techniques offline with pencil and paper.