About Precision Sudoku
Precision Sudoku is a free Sudoku trainer built around one idea: difficulty labels are the wrong unit of practice. “Hard” means different things to different publishers — what actually makes a puzzle hard is the specific solving techniques it requires. So instead of picking a star rating, you pick the techniques you want to practice, and the site serves a puzzle that requires exactly those techniques: no more, no less.
That guarantee is the core of the site. Every puzzle in our collection has been solved by our own step-by-step logical solver, which records precisely which techniques the puzzle demands. When you ask for an X-Wing puzzle, the X-Wing is genuinely required — the puzzle cannot be completed without it. This is how pattern recognition is actually built: repeated exposure to a known pattern, with feedback, rather than hoping the right situation shows up in a random puzzle.
What's here
- The technique picker — choose from twelve techniques, from Naked Singles through Swordfish, and play puzzles guaranteed to require them.
- Interactive lessons — each technique has a teaching page with a live mini-demo, spotting advice, common mistakes, and FAQs. Start with the learning-order guide if you are unsure where to begin.
- Worked walkthroughs — real puzzles with full pencil-mark boards showing each technique before and after it fires.
- Long-form guides — the history of the puzzle, the mathematics behind it, and the craft of solving well.
The player itself is deliberately elimination-first: you remove candidates you can justify removing, and a cell resolves when a single candidate remains. It is a small design choice with a point — eliminations, not guesses, are what solving is made of.
Who runs it
Precision Sudoku is an independent project built and maintained by a software developer and long-time Sudoku enthusiast. There is no puzzle-media company behind it, no account to create, and nothing to buy. The site is supported by advertising; how we handle data is covered plainly in the privacy policy.
Contact
Found a bug, spotted an error in a guide, or have a technique you would like to see added? Email support@bamcis.org. Corrections are especially welcome — the guides make factual claims about history and mathematics, and we would rather fix a mistake than defend one.