Named patterns · Free
Sudoku techniques
Every technique below has a full page with diagrams, walkthroughs and FAQs. Start at Beginner and only move up when the current level feels automatic.
Intermediate techniques
Intermediate
Naked Pair
A Naked Pair is two cells in the same row, column or 3×3 box that each carry exactly the same two candidate digits — meaning those two digits are locked into those two cells, and can be eliminated from every other cell of that unit.
Open guide →Intermediate
Hidden Pair
A Hidden Pair is two digits that can only go in the same two cells of a row, column or 3×3 box — even though those two cells may still carry other candidates too. Once found, every other candidate can be stripped from those two cells.
Open guide →Intermediate
Pointing Pair
When a digit's only candidates inside a 3×3 box all sit on the same row (or column), that digit must come from that box on that row — so it can be eliminated from the rest of the row (or column) outside the box.
Open guide →Intermediate
Box/Line Reduction
Box/Line Reduction is the mirror of Pointing Pair: when a digit's only candidates on a row or column all sit inside one 3×3 box, that digit must come from that box on that line — so it can be eliminated from the rest of the box.
Open guide →Advanced techniques
Advanced
X-Wing
An X-Wing is a rectangle of four cells where a single candidate digit appears in exactly two cells of two different rows — and those four positions line up in the same two columns. That candidate can then be eliminated from those two columns everywhere else.
Open guide →Advanced
Swordfish
A Swordfish is a three-row (or three-column) generalisation of X-Wing: a candidate digit's positions across three lines collapse onto the same three cross-lines, which forces the digit into those cross-lines and clears it from every other cell on them.
Open guide →Advanced
XY-Wing
An XY-Wing is a three-cell chain — a pivot with two candidates and two pincers, each sharing one candidate with the pivot and one shared 'link' digit with each other — that eliminates the link digit from any cell that sees both pincers.
Open guide →How to practice techniques
- Read one technique page end-to-end.
- Play a Medium or Hard board looking only for that pattern.
- When stuck, one Hint — then identify which technique it used.
- Repeat tomorrow before learning the next pattern.
Also: how to get better · when stuck · solver
FAQ
- What are the most important Sudoku techniques?
- Hidden Single, Naked Pair and Pointing Pair cover the majority of Easy through Hard boards. Add X-Wing when Medium feels automatic.
- In what order should I learn Sudoku techniques?
- Beginner singles → pairs → pointing / box-line → fish (X-Wing, Swordfish) → wings (XY-Wing). Do not skip pairs to chase advanced patterns.
- Are Sudoku techniques the same as tips?
- Tips are habits (scan by digit, take breaks). Techniques are named logical patterns that force a placement or elimination. You need both.