The Minochantha group consists of 3 stupas. They are non-pentagonal representations of the hpaya-nga-zu theme. The other non-pentagonal temple with this theme is the Penathagu (Pe-na-tha-gu) group. The hpaya-nga-zu theme is an iconographic portrayal of the ‘Five Sacred Lords’ depicting five buddhas seated in niches beneath the stupa. I did not take any pictures of the interior. -Strachan, p. 123
Because there are 3 of them they are also referred to as the Three Sisters.
There is not much written about these temples that I could find, other than what Strachan wrote and from Pierre Pichard’s Inventory of Monuments. They are small stupas built with brick masonry. They are all whitewashed with circular bell-shaped domes at the top with conical spires and umbrellas. Construction is estimate to be in the 11th century and it has been restored. Decoration includes stucco moulding on bases and terraces, dado with triangles, and ornate waistband and frieze with ogre heads around the dome.
References:
Ancient Pagan: Buddhist Plain of Merit, Donald Stadtner, River Books, 2013
Pagan: Art and Architecture of Old Burma, Paul Strachan, Kiscadale Publications, 1989
Guide to Bagan Monuments by Min Bu Aung Kyaing, U Zaw Min Aye (Zaw Press), 2007
Inventory Of Monuments In Bagan, Pierre Pichard, UNESCO, 8 volumes, 1992-2001