Learn sudoku
From the rules to an X-Wing, in the order the app teaches it: read the guide, then drill the move until you see it at a glance.
Start with the rules
New to sudoku, or back after a while? These two guides take you from the rules to a full solve.
Sudoku Rules: The Only 3 Rules You Need to Know
The complete rules of sudoku explained in plain language. Every row, column, and 3x3 box must contain 1-9 exactly once.
Read the guideHow to Solve Sudoku: A Step-by-Step Method
How to solve any sudoku, step by step: the scanning loop for singles, when to add pencil marks, which techniques to try in which order, and what to do when you are stuck.
Read the guideThe technique ladder
Thirteen techniques, easiest first. Each guide has a worked example from a real puzzle, and each technique has a drill in the app.
Filling a cell
- Full HouseThe full house (last remaining cell) is the simplest sudoku placement. How to spot it instantly and why it matters for your solve times.Drill it
- Naked SingleWhat a naked single is, how to spot one without counting to nine, and how it differs from a hidden single. With examples and practice tips.Drill it
- Hidden SingleHidden singles place more digits than any other technique in most sudoku puzzles. Learn the rule, a worked example and a fast way to scan for them.Drill it
Eliminating candidates
- Pointing PairsTwo related techniques that eliminate candidates by analyzing how boxes and lines interact. Essential for intermediate solvers.Drill it
- ClaimingClaiming, also called box-line reduction, removes candidates from a box. Learn the rule, follow a real example, and see how to spot it while solving.Drill it
- Naked PairMaster the naked pairs technique, one of the most useful intermediate sudoku strategies, with clear visual examples.Drill it
- Hidden PairA hidden pair is two digits confined to the same two cells. How to find hidden pairs by counting digits, what to eliminate, and a worked example.Drill it
Advanced patterns
- Naked TripleHow naked triples work, why no cell needs all three digits, how to find them, and how they relate to naked pairs and quads.Drill it
- Hidden TripleA hidden triple is three digits that fit in only three cells of a group. A worked example and the shortcut that makes them easy to find.Drill it
- X-WingThe X-Wing pattern is a powerful advanced sudoku technique. This visual guide shows you exactly how to find it and how to use it.Drill it
- SwordfishThe Swordfish extends the X-Wing to three rows and three columns. Learn this expert-level technique with a step-by-step example.Drill it
- XY-WingHow the XY-Wing works, why one pincer must hold the shared digit, which cells you can clear, and how to search for the pattern.Drill it
- Simple ColoringHow simple coloring (simple colouring) works: build a two-color chain on one digit and use the color wrap and color trap rules to eliminate candidates.Drill it
The Dojo: drill one technique at a time
The Dojo is the technique trainer inside Sudoku Royale. A drill skips the rest of the puzzle and shows you one board after another where a single technique is the next move.
Open a drill in the app
13 drills, one per techniqueKeep reading
Strategy, speed, the daily puzzle, and patterns beyond the ladder.