Learn Sudoku one clear step at a time.
Start with the rules, build accurate candidate notes, and add stronger techniques only when simpler deductions stop. Every guide explains what to look for, why the move works, and what to check next.
Beginner
Build a reliable foundation and solve without guessing.
Learn the complete rules of classic 9×9 Sudoku, what counts as a valid move, and how to begin a puzzle without guessing.
Read guide →Beginner · 7 minSudoku Candidates and NotesUse candidate notes accurately, keep pencil marks readable, and turn possible digits into reliable Sudoku deductions instead of clutter.
Read guide →Beginner · 5 minHow to Find Naked SinglesLearn how to identify a Sudoku cell with exactly one legal candidate, verify the placement, and use the result to unlock nearby cells.
Read guide →Beginner · 6 minHow to Find Hidden SinglesFind digits that have only one possible position inside a row, column, or box, even when the target cell shows several candidates.
Read guide →Beginner · 8 minA Beginner Sudoku Solving OrderFollow a repeatable Sudoku workflow that moves from simple scans to candidates and patterns without guessing or searching at random.
Read guide →Intermediate
Use candidate relationships to unlock crowded grids.
Learn how candidates confined to one row or column inside a 3×3 box eliminate the same digit from cells outside that box.
Read guide →Intermediate · 8 minHow Naked Pairs Work in SudokuIdentify two cells that contain the same two candidates and use their locked relationship to eliminate candidates from a shared unit.
Read guide →Advanced
Recognize larger patterns after the basics are exhausted.
Read a technique, then use it.
Sudoku0’s Explain control previews the next supported step before it changes the board. That makes a live puzzle a useful companion to these guides.