Boa Enduri (also Ba Enduri, and addressed by the honorific Sangia Mapa, 'great old man of the sky') is the supreme heaven-deity of the Nanai of the lower Amur and Ussuri. The name joins boa / ba, 'sky, heaven, world' — cognate with the pan-Tungusic concept buga of sky and universal deity — to enduri, the ordinary Nanai word for a god. He rules the Upper World, which the Nanai imagine as a layered vault of clouds and tiers (three copper, silver and golden layers in some tellings, nine layers in the account A. V. Smolyak recorded). Above the masters of the earth (Na Endurini), the taiga (Duente Edeni) and the water (Temu), the heaven-deity stands as the highest of the enduri, the guarantor of cosmic order in a living folk religion still practised on the Amur.