The statue was derived from the legend that the Prince Shōtoku clasped his hands in prayer toward an eastern direction to chant “Namubutsu” in spring when he became two years old. The statues as a single image of Namubutsu Taishi were dated back to the early Kamakura period in the literature, however the actual examples were increased after the late Kamakura period.
 
Shigeki Iwata 
Masterworks from the Nara Buddhist Sculpture Hall at the Nara National Museum. Nara National Museum, 2010, p.139, no.150.