According to a theory, both the Emperor Sushun and the Empress Suiko were enthroned due to the fact that Takeda no miko was still a minor, then he became the Crown prince Umayado (厩戸皇子立太子) since he died soon after the enthronement of the Empress Suiko.
また、一説には崇峻天皇即位時、推古天皇即位時には竹田皇子が未だ成年に達していなかった為即位が見送られ、推古天皇即位後間も無く薨去したため厩戸皇子立太子となったともいう。