Five connected grids
Follow the shared boxes through five grids
Samurai Sudoku joins five 9×9 grids through four overlapping 3×3 boxes. Every grid follows ordinary Sudoku rules. A shared cell has one value that must satisfy both grids, so progress in a corner can unlock a move in the center.
01
Begin with one manageable grid
Choose a grid with useful givens and look for ordinary singles. Keep your attention there until a placement changes one of its shared boxes.
02
Check both sides of the overlap
A digit placed in a shared box belongs to both grids. Check its rows and columns in each grid before moving to another corner.
03
Keep shared candidates consistent everywhere
A candidate in an overlap must survive the restrictions from both grids. Update that shared cell’s notes after changes on either side of the connection.