Sudoku Guides

These guides go a step beyond the basics. Each one takes a single idea — a solving technique, a variant, or a way of reading the board — and works through it slowly, with plain-language reasoning and worked examples you can try on a real grid. They are written for players who already know the rules and want to get genuinely better, whether that means finally cracking your first hard board or learning a variant like Killer or Flower Sudoku from scratch.

New guides are added on a regular cadence, so it is worth checking back. Start with whichever title speaks to where you are stuck right now; you do not need to read them in order.

• VariantsHow to Solve Samurai Sudoku (5 Grids)How to solve Samurai Sudoku (Gattai-5): start with the four overlap boxes, work the fullest grid, and let one placement ripple across two grids at once.
• VariantsDiagonal Sudoku (Sudoku X): Rules & StrategyLearn Diagonal Sudoku (Sudoku X): the one extra diagonal rule, why it helps you solve, and why starting at the centre cracks the board fastest.
• VariantsGreater Than Sudoku: Rules & How to SolveLearn Greater Than Sudoku: how the < and > signs work, how to find the 1s and 9s first, and how to solve a board with few or no given numbers.
• ChainsThe Skyscraper Technique in SudokuA guide to the Skyscraper: a single-digit pattern whose two strong links remove a candidate from the cells both roofs see, cracking hard grids.
• ChainsSimple Coloring: Chains for a Single DigitA guide to simple coloring in sudoku: follow one digit’s strong links with two colors to prove which cells it cannot occupy and crack tough boards.
• WingsThe XY-Wing: A Three-Cell Chain ExplainedA guide to the XY-Wing: how a pivot cell and two pincers built from three bi-value cells force an elimination that singles and pairs can never reach.
• IntersectionsPointing Pairs and Box/Line ReductionA guide to intersection removal: how pointing pairs and box/line reduction use where a box and a line overlap to eliminate candidates and open a grid.
• SubsetsNaked and Hidden Triples: The Next StepA guide to naked and hidden triples — the three-cell version of pairs — how to spot them and the eliminations they unlock on hard boards.
• SubsetsNaked and Hidden Pairs: Get Past a Stuck GridA guide to naked and hidden pairs: the two mid-level Sudoku techniques that get you moving again when simple scanning and singles stop working for you.
• FishX-Wing and Swordfish: Advanced Sudoku TechniquesLearn two advanced Sudoku techniques, the X-Wing and the Swordfish, with clear step-by-step reasoning that breaks open the hardest boards you will meet.
• VariantsKiller Sudoku Guide: Cages, Sums & Rule of 45A complete guide to Killer Sudoku: how cages and sums work, the cage combinations worth knowing, and the rule of 45 that quietly unlocks the whole grid.

How to get the most from these guides

Reading about a technique and owning it are two different things, and the gap between them is closed at the board, not on the page. The most effective way to use a guide is to keep a puzzle open alongside it: read a step, pause, and hunt for that exact pattern on your own grid before moving on. A technique you have found once with your own eyes sticks far better than one you have only read about. It also helps to learn them roughly in order of difficulty — hidden singles and pairs carry you through most boards, and only the hardest grids call for pointing pairs, colouring or the wing techniques.

Which guide should you read first?

If hard puzzles routinely stall you, start with naked and hidden pairs, then pointing pairs — between them they unlock the great majority of "stuck" positions. If you are drawn to a particular variant, read its guide before you play: knowing how a Killer cage or a Flower region changes the logic turns a frustrating first game into an enjoyable one. And if you are comfortable on medium boards but want to break into expert play, the X-Wing and XY-Wing guides are the natural next step. Pair any of them with the quick reads over on Tips for the habits that make every solve smoother.