Sudoku guides
Step-by-step articles on rules, candidate notes, and named solving techniques—written for players who want a logical next step.
Featured guide
The Complete Guide to How Sudoku Works
Learn how Sudoku works, including the 9x9 grid rules, candidate notes, elimination methods, difficulty levels, and a practical solving example.
16 min read
More guides
5 Ways to Approach Number Puzzles Like Sudoku
Learn how to solve number puzzles with five practical Sudoku approaches: map constraints, scan for singles, track candidates, test deductions, and avoid guesses.
6 min read
9 Advanced Sudoku Techniques That Experienced Solvers Use
Learn 9 advanced Sudoku techniques, including X-Wing, Swordfish, XY-Wing, coloring, chains, and unique rectangles, with practical examples.
12 min read
How to Solve Sudoku Without Guessing
A logical Sudoku solving workflow: scanning, pencil marks, singles, pairs, triples, pointing, claiming, fish, and chains, with worked grid examples.
12 min read
Techniques
One page per pattern, from singles through fish and wings. Start with how to solve Sudoku without guessing if you want the order to use them in.
Naked Singles
A naked single is a Sudoku cell with one candidate left. Learn when to place it, how to spot it, and the mistakes that turn a single into a wrong digit.
5 min read
Hidden Singles
A hidden single is a digit with one cell left in a row, column, or box. See a worked example, how to spot it among longer notes, and the mistakes to avoid.
5 min read
Naked Pairs
A naked pair is two cells in one unit that share the same two candidates. Learn the elimination, a worked row example, how to spot pairs, and common mistakes.
5 min read
Hidden Pairs
A hidden pair is two digits that share only two cells in a unit. Learn how the elimination differs from a naked pair, with a worked example and common mistakes.
5 min read
Naked Triples
A naked triple is three cells in one unit whose candidates use only three digits. See the patterns that qualify, a worked example, and the mistakes that do not.
6 min read
Pointing Pairs
A pointing pair locks a Sudoku candidate to one row or column inside a box. Learn the elimination, how to spot it, a worked example, and common mistakes.
6 min read
Box-Line Reduction
Box-line reduction, or claiming, locks a Sudoku digit on one row or column into a single box. See a worked example, how to spot it, and how it differs from pointing.
6 min read
X-Wing
An X-Wing locks one Sudoku digit to two columns in two rows, or two rows in two columns. See the rectangle rule, a worked example, and the mistakes that break it.
6 min read
Swordfish
A Swordfish locks one Sudoku digit to three columns across three rows, or three rows across three columns. See a worked example, how to spot it, and common mistakes.
7 min read
XY-Wing
An XY-Wing uses three bivalue cells — a pivot and two wings — to delete one candidate from every cell that sees both wings. Worked example, how to spot it, and common mistakes.
6 min read