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Everything we know about solving sudoku

Six pages, no fluff: the rules, the measured definition of difficulty, the habits that block progress, and a plan for the next four weeks.

The rule, the notation, and the three questions that solve every Easy puzzle.

Real measurements: clue counts barely change, techniques change everything.

The behaviours that turn a logic puzzle into a guessing game.

One skill per week, at a difficulty where you can actually practise it.

R1C1, boxes, candidates, peers — the vocabulary every guide assumes.

6.67×10²¹ grids, the 17-clue proof, and why uniqueness matters.

Technique library

Each technique page explains the pattern, why it is valid, and how much it adds to a puzzle's score — with a replayable example.