Sudoku Academy
Learn Sudoku from first move to expert solve
A guided path through everything we publish about Sudoku. Read the rules, build a solving toolkit, calibrate your skill against difficulty, then take on Killer.
You don't have to read it in order. But if you're new, the order works. Each step builds on the last and points to specific pages on this site.
Step 1
Foundations
Start here if Sudoku is new to you. The rules are short. The hardest part is reading the board confidently before you make your first move.
Step 2
The solving toolkit
Every named technique, layered easiest to hardest. Read them in order or jump to the one that's stopping you on a hard board.
Basic techniques
Naked singles, hidden singles, locked candidates, naked pairs. The first 80% of any solve.
Advanced techniques
Hidden pairs, X-Wing, Swordfish, XY-Wing. The first techniques that need pencil marks to spot.
Master techniques
Jellyfish, unique rectangle, empty rectangle, coloring, chains. Used sparingly even on expert boards.
Technique atlas
Every named technique in one place, grouped by family. Use it as an index when a board mentions a name you don't know.
Step 3
Practice by difficulty
Calibrate. Easy boards are for habit-building; hard boards are where the named techniques start paying off. Both have a place.
Step 4
Killer Sudoku
Same digits, different game. Cages and target sums replace given clues, and arithmetic becomes part of the logic.
Killer overview
The rules of Killer, how cages work, and the patterns that crack the first cells.
Cage combinations reference
Every cage size and sum, with the digit combinations that make it possible. Includes the locked-combination cheat sheet.
Killer techniques
Rule of 45, innies and outies, hidden combinations, cage splitting, pseudo-cages. The techniques that don't exist in classic Sudoku.
Ready to play?
The web board is free. No account, no install. Open it whenever you want a quick puzzle or a long session.
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