Prince Shotoku (574 - 622 CE) was an imperial prince of the Yamato court of Japan and an influential spiritual leader as well. His father was the Emperor Yomei, who was the first emperor of Japan to fully embrace Buddhism as a national religion. Yomei gave Umeyado (the prince's given name) an excellent education in Buddhist philosophy, metaphysics, and Chinese culture. When Yomei passed away, his sister Suiko became Empress. Though he was considered too young to rule alone, the Empress made Shotoku her regent and proclaimed him de facto ruler in 593. The young prince was so trusted by the court and Japan that he was renamed shortly before his succesion to the throne. The new name; Shotoku; means 'holy and virtuous'.
Immediately after ascending to the throne, Shotoku proclaimed Buddhism the state religion. He also began construction on the Tenno-ji, a Buddhist complex that contained a college, monestary, hospital, and an asylum. Most other Buddhist complexes of the time followed his model. He also built a temple near Osaka, so that all those travelling in and out of Japan would pass through it. During his rule, he built 46 Buddhist temples including the Horyuji and Yumedono (Chapel of Vision) dedicated to Kwannon (Kwan-Yin). The most important temple he built was the Hokoji, the main temple of the Soga clan, which still protects Shotoku's commentaries on the Lotus Sutra. Several other temples in Japan claim to have been built by Shotoku, but archaeological evidence shows otherwise.1
The prince was also a great statesman and diplomat. He always balanced Japan's relations with Korean kingdoms so that no one kingdom would gain advantages over the other. He also frequently kept in touch with the Chinese emperor, mostly for the cultural influence. The Chinese emperor sent over Chinese and Korean artists and monks to Japan at the prince's request. Shotoku also encouraged these new monks to teach at the monestaries he built and to the people of Japan, though he himself remained dedicated to Sanron Buddhism. The treatises of Nagarjuna are the basis for Sanron. Since most humans are considered 'unredeemable', they must follow Nagarjuna's 'instructions' in order to find truth and reach nirvana.2
Prince Shotoku is most famous for the kempo, or constitution that he wrote in 604 CE. It is usually called The Constitution of the Seventeen Articles. It is not really a set of laws, but rather another treatise that laid down moral and political issues dealing with government, and with the lives of the people of Japan. It borrowed from the Analects of Confucius, but most was strictly Japanese in origin. In addition to penning the Constitution, Shotoku also wrote commentaries on the Lotus Sutra (Hokke-kyo), the Vimalakirti Nirdesha Sutra (Yuima-gyo), and the Lion's Roar of Queen Shrimala (Shoman-gyo).
Shotoku's most important contribution to Japan was his belief in a centralized government run by those who had merit, and not those who had inherited positions. He also did not advocate himself as a descendent of Amaterasu (the Sun goddess), and believed that the leader of Japan should also be chosen through merit.
1 - Theosophy Library Online
2 - Sanron information from Dr. John Herman's lecture, 01/18
Links used in compiling this node:
http://theosophy.org/tlodocs/teachers.html
http://www.albany.edu/eas/190/shotoku.htm
Special thanks to my Japanese Religion Teacher Dr. Herman.