Detour

Novice monks spread freshly washed clothes out onto the cobblestone courtyard. Arthritic, bead-clutching Buddhist nuns shuffle around the Rumtek Dharma Chakra Centre, accumulating merit with every leisurely lap. If it weren't for the guards on the rooftop, toting antique Enfield rifles, the 273-year-old Rumtek Monastery would be a vision of calm.

A two-hour, tooth-loosening drive west of Gangtok, Sikkim's capital, the monastery is at the center of a divisive and sometimes violent battle within Tibetan Buddhism's Kagyupa (Black Hat) sect: Who is the rightful 17th Karmapa? Is it the New...