Brutal Sudoku Online
Brutal sudoku puzzles are the very hardest we have. This is the level for you if you solve extreme puzzles without much trouble and want to test the limits of what can be solved with paper, a pencil, and sheer willpower. The puzzles are free, and there is no limit on how many you can play.
Every brutal puzzle is verified by our solving engine and has exactly one solution that can be reached with logic alone. But be warned: the key moves are often hidden behind long chains of reasoning, and even very experienced players take their time here.
The techniques behind brutal puzzles
At this level, chain techniques are unavoidable. Alternating inference chains, known as AICs, alternate between strong and weak links across the puzzle and produce eliminations at both ends of the chain. Forcing chains test both candidates in a cell and follow the consequences until they meet in a shared conclusion.
You will also encounter patterns such as ALS, where two almost locked sets are linked together, Kraken Fish, which are fish patterns with an extra fin, and 3D Medusa, which colors across several digits at once. These are the heaviest tools in the sudoku world.
Strategy for reaching the finish line
Perfect notes are not optional here. A single missing candidate can hide the chain you need. Many players also mark links with colors to keep track of the chains, just as the simple coloring technique suggests.
Use our technique pages to learn the patterns thoroughly before you start, and use the sudoku solver when you are completely stuck. It shows you the next step with the full reasoning, so you can see how the chain is built. Completing a brutal puzzle also rewards you with more XP than any other level.
Techniques you need at this level
These are the most advanced techniques in our collection, and on brutal puzzles you will need them. Each technique has its own page with interactive examples that show you the pattern step by step.