Select techniques you’d like to practice.
Most Sudoku sites ask you to choose a difficulty label, which is a poor description of what you are about to face. “Hard” means whatever the publisher decided it means, and two puzzles carrying the same label can demand completely different reasoning. What actually determines the difficulty of a grid is the set of solving techniques it forces you to use.
So this picker asks for those directly. Tick the techniques you want to work on and the site serves a puzzle that requires exactly those and nothing harder. That guarantee is not an estimate: every puzzle in the library has been solved by our own step-by-step logical solver, which records precisely which techniques the grid demands. When you ask for a Swordfish, the Swordfish is genuinely unavoidable.
Ticking several techniques asks for a puzzle needing all of them, so a wider selection produces a harder and less predictable grid. Ticking one produces focused repetition, which is the faster way to make an unfamiliar pattern automatic. The question mark beside any technique opens its lesson page.
Games you leave unfinished are kept on this device and reappear above the technique list, so a puzzle abandoned mid-solve can be picked up later without an account or a login. Nothing here requires signing up, and no progress is stored on a server.
If you are not sure where to start, the technique learning order explains which patterns build on which, and the practice pages offer the same puzzles pre-selected one technique at a time.