Puzzle entry
Sudoked first checks whether your puzzle has exactly one solution, then follows the easiest available human technique at every position. Each deduction preserves its exact candidate state, so you can move backward, jump through the solution path, and inspect advanced patterns like X-Wing, XY-Wing and Swordfish without losing context. The result is a complete, replayable solving path you can study one step at a time.
If the supported logical techniques reach a dead end, the Sudoku solver says so. Any remaining verified search placements are clearly separated from human deductions—they are never presented as a technique that was not actually found. You always know exactly which logical strategy produced each elimination or placement.
From beginner deductions to advanced patterns, every step is named and visualized so you can learn the logic behind it. The solver applies techniques in order of difficulty, always choosing the simplest one that works next:
Want to practice a specific strategy? Try the Sudoku Trainer for hand-picked positions, or browse the full Sudoku techniques guide.