A similar earlier example is illustrated in Zwalf, W. (ed.), Buddhism, Art and Faith, (British Museum, London), no. 366.
The Imperial prince Shotoku Taishi was a pivotal figure in Japanese history and is credited with the formulation of the first national constitution, the compilation of a national history and encouraging the introduction of Buddhism from China. He encouraged intercourse with China, and the adoption of much of its court culture. He is often represented as a child, a young adult praying for his father's recovery, or as the adult regent. In this case, he is represented in the tradition of the Kamakura period as a child reciting mantras, in the namu Amida butsu [hail to Amida Buddha] pose.