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.

• 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.