Built by Solvers, for Solvers — the resource we wish had existed when we started.
Welcome to the Sudoku Index. If you're here, you probably know the feeling of staring at a 9x9 grid until the numbers start to blur — hovering your pencil over a cell, certain that something logically follows, but not quite sure what it is.
The Sudoku Index didn't start as a business. It started as a personal quest to find order in the chaos. Like many of you, the journey began with "Easy" puzzles in the Sunday paper, armed with a dull pencil and far too much confidence. The "Medium Wall" appeared quickly — and when we looked for help online, we found either overly academic research papers, or sites cluttered with ads and pop-ups that made it impossible to focus on a puzzle, let alone learn from one.
We built this site to be the resource we wish we'd had when we first encountered an X-Wing pattern and had absolutely no idea what we were looking at.
The Sudoku Index exists to bridge the gap between "casual filler" and "logical mastery." We believe the barrier between Easy and Expert difficulty is not intelligence — it's vocabulary. Once you know what a Naked Triple looks like, you see them everywhere. Once you understand the X-Wing rectangle, it stops being intimidating and starts being exciting.
We only feature puzzles with a single, logically provable solution. Guessing is never required — and we prove it.
Advanced techniques shouldn't be secrets. We break down Swordfish and Jellyfish patterns in plain, jargon-free English.
Sudoku is a rare form of digital detox. We help you find the "flow state" where the rest of the world fades away.
Every guide has been tested against real puzzles. We don't just describe techniques — we apply them to actual grids to verify that the explanations work in practice, not just in theory.
We curate, not just aggregate. Our Resources page only lists apps and books we'd genuinely recommend to a friend — with honest assessments of who each tool is best for.
We progress with you. From the Beginner's Guide and Cheat Sheet through to the full Glossary and X-Wing techniques, every level of solver is catered for.
Ad-free learning experience. Our guides and strategy pages are designed to be distraction-free. When you're trying to understand a Pointing Pair, the last thing you need is a pop-up.
No guessing. Ever. This is non-negotiable. Every guide on this site is built on the principle that Sudoku is a game of 100% logical certainty. We will never suggest trial-and-error as a valid solving method.
Here's how the Sudoku Index content is structured to take you from your first grid to expert-level mastery:
Whether you're picking up Sudoku for the first time or looking to crack your first X-Wing, we've built a clear path forward.
Start with the Beginner's Guide Browse the Directory