Just a short walk (approximately 10 minutes) from Lhakhang Karpo lies Lhakhang Nagpo, or the “Black Temple,” also attributed to King Songtsen Gampo in the 7th century. Legend states that this temple was built on the spot where the black pigeon landed, indicating its auspicious location. The temple’s walls are painted black, with horizontal stripes of red and white, symbolizing the tantric practices prevalent in the valley in ancient times.

Lhakhang Nagpo is said to be built on an subterranean lake, with a small hole in the temple floor allowing a glimpse into the underground water. It serves as the seat for the guardian deity Da Do Chen and houses the principal relic of the monastery, the Choe-Lung-truel Sum. Both Lhakhang Karpo and Lhakhang Nagpo are considered guardian sentinels, watching over the southern entrance of the Haa Valley and offering a unique insight into Bhutan’s early Buddhist and shamanistic history.