Samurai Sudoku

Expert samurai sudoku

Expert puzzles give you 50 to 79 givens for 405 cells. That's sparse enough that individual grids look almost empty. Scanning the center grid first still works as a starting strategy, but you'll often find that even the center doesn't yield much without corner-grid information flowing inward.

The defining feature of expert samurai is multi-grid deduction chains. You might eliminate a candidate in the top-left grid's shared box, which forces a placement in the center, which eliminates something in the bottom-right shared box, which finally solves a cell in the bottom-right corner. These chains span three or four grids and can take a while to trace.

Heavy use of pencil marks is non-negotiable. Hidden pairs and triples in individual grids come up regularly, and you need accurate candidate lists across all five grids to spot them. The cross-grid auto-candidates mode helps, but you still need to interpret the results.

Expect 40 to 75 minutes per puzzle. Einstein pushes this further with under 50 givens and logic-only certification.