Sudoku Strategies, From Singles to X-Wing and Beyond
Every sudoku technique in the order you need it, from hidden singles to X-Wing, XY-Wing and colouring, each with a worked example you can check by hand.
Sudoku guides and strategies
Rules, techniques from singles to X-Wing, the small 6x6 grid and where the puzzle came from.
6x6 Sudoku: Rules, 2x3 Boxes and Tips for the Small Grid
How 6x6 sudoku works: digits 1 to 6, six boxes of 2x3, the tricks the rectangular boxes allow, a full solve move by move, and when to move up to 9x9.
How to Play Sudoku: The Rules and Your First Solve
The rules of sudoku, three questions that find a digit, and a complete 6x6 grid solved move by move, plus notes and what to do when you get stuck.
Naked and Hidden Pairs in Sudoku, Explained With Examples
How naked and hidden pairs and triples work in sudoku, why they are safe, how to spot them fast, and worked examples you can check yourself.
Sudoku Notes (Pencil Marks): When and How to Use Them
Full notes, two-square marks, corner and centre styles, when notes save time and when they waste it, and how to keep them tidy, with a worked box.
The History of Sudoku: From Number Place to the 2005 Craze
Who invented sudoku and how it spread: Euler's Latin squares, Howard Garns and Dell's Number Place, Nikoli's name, and Wayne Gould's Times puzzles.
Why a Good Sudoku Has Exactly One Solution
What a unique solution means in sudoku, why logic-only solving depends on it, the 17-clue proof of 2012, and how puzzle makers check that a grid has one answer.
X-Wing and Swordfish: Sudoku Fish Patterns Made Simple
How the X-Wing and Swordfish work in sudoku, in rows and in columns, how to scan for them, and worked examples you can check, plus one to try.