Sudoku Strategy & Technique Hub
From essential beginner candidate pruning to advanced fish and wing patterns. Master solving logic with step-by-step visual explanations and interactive hands-on boards.
Naked & Hidden Singles
The foundation of solving. When 8 other numbers occupy a house, only one single legal number remains.
Pointing Pairs
When candidates inside a 3ร3 box align on a straight line, they point outward and eliminate candidates across the row or column.
Box-Line Reduction
When a row or column confines a candidate to a single 3ร3 box, that line claims the digit and eliminates it from the rest of the box.
Naked Pairs
Two cells in the same row, column, or block containing the exact same two candidates. Lock the digits in place and clear the unit.
Hidden Pairs
Two digits that appear in only two cells within a unit. Clear all extraneous noise pencil marks from those two cells.
Hidden Triples
Three specific digits restricted to only three cells within a house, allowing all other candidates in those cells to be eliminated.
X-Wing Pattern
A 4-cell rectangle across two rows sharing the same columns. One of Sudoku's most famous fish techniques.
XY-Wing (Y-Wing)
A 3-cell pattern with a pivot and two wings. Eliminates candidate Z from all cells seeing both pincer wings.
Swordfish
A 3-row, 3-column extension of the X-Wing. Powerful candidate elimination that breaks open expert-tier puzzles.
Stuck on a tricky puzzle?
Test any real grid in our interactive Sudoku Solver to discover the exact next deduction step.