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Learn to solve sudoku with notes
Practical guides to solving without guessing, written around the NOTE-KU method. Start with the first one if you’re new.
How to Solve Sudoku Without Guessing
A complete approach that works from easy to extreme.
Read ▸Sudoku Notes, Pencil Marks and Candidates, Explained
What a note really means, and how to take notes you can trust.
Read ▸The Two-Candidate Rule: When to Write a Sudoku Note
The single rule that keeps your notes clean and meaningful.
Read ▸Stuck on a Sudoku? Test, Don’t Guess — Temp Mode
How to test a candidate safely and prove the answer by contradiction.
Read ▸Sudoku and the Brain: What Brain-Imaging Research Shows
What a 2026 review of brain-imaging studies found — and its limits.
Read ▸Prefer the whole picture?
The Method explains NOTE-KU end to end, and How to Play covers every button in the app.