What is "lukhang"

Lukhang (Tib. klu khang, residence of Nagas), formally Zongdag Lukhang (Tib. rdzong bdag klu khang [?], residence of Nagas, lords of the castle and administered territory [?]) is the name of a secret temple of Lozang Gyatso, 5th Dalai Lama. Three walls of the temple are covered with murals of yogis engaged in their exercises.

• One wall of murals illustrates a commentary by Longchenpa on a Dzogchen tantra Rigpa Rangshar, interpreted according to the 5th Dalai Lama's experience of practice. The murals show characteristic visions of the secret practice of thödgal.
• Another wall shows eight manifestations of Guru Padmasambhava and eighty four main Mahasiddhas.
• The third wall illustrates positions and movements of Yantra Yoga.

The temple is situated on a small island on a lake behind the Potala palace in Lhasa.