Muay Thasao (Muay from the village of Thasao) is a Muay Boran style that refers to a swordsman named Phraya Pichai Daap Hak, who lived during the Thonburi Era (1768-1782 A.D.).
However, the authenticity of this story is highly controversial in professional circles, as there are many different versions of it that tell different things. None of these stories suggests that Phraya Pichai Daap Hak ever passed on his knowledge as a teacher or that he was qualified as such (Krob Kru).
Likewise, there is no evidence that he ever fought in a boxing ring. There is no evidence of a local connection between Phraya Pichai Daap Hak and the village of Thasao.
The fighters of Muay Thasao became known only relatively recently through the (potentially fictional) stories of Ajarn Ket Sriyapai. Not a single Muay Thasao fighter has ever qualified in anything other than Muay Thai (Krob Kru).
Although Muay Thasao supposedly exists for several centuries, there is still no independent teaching concept.