Wikipedia
Shunbajunki
was a king of the Ryūkyū Islands. Shunbajunki was the second of the Shunten Line. He succeeded his father Shunten in 1237.
Shunbajunki's reign is noted for the construction of Shuri Castle, and the introduction of the Japanese kana writing system. The Chinese language and writing system was not to be introduced until roughly a century later; even after that time, government documents continued to be written in kana, as did much poetry.
Shunbajunki died in 1248, and was succeeded by his son Gihon.