I heard she was based on Hata no Kawakatsu. But maybe she can be both.
Ah. I'm sorry. I wasn't clear enough. Prince Shōtoku comissioned Hata no Kawakatsu to make the masks and further had Kawakatsu perform with it, thereby officially making/acknowledging the art of Noh. Shōtoku is credited with making Noh come into being, but Kawakatsu should get the credit for making the actual mask.