How do you tune a santoor?

Each course of a santoor has several strings that sound one note, so the player brings every string in a course to the same pitch. The traditional Kashmiri santoor has 100 strings in 25 courses of four. Shivkumar Sharma's 31-bridge, 91-string instrument is tuned chromatically across three clear octaves, and string and bridge counts vary between makers and players.