- Born: 1815
- Died: 1851/7/25
- Other Names: 渋川六蔵 (Shibukawa Rokuzou)
- Japanese: 渋川 敬直 (Shibukawa Hironao)
Born in Edo the eldest son of Shibukawa Kagesuke in 1815, he was named apprentice to the Tenmongata (chief astronomer and calendrics master) of the Tokugawa shogunate in 1831. With the aid of his father, he edited or compiled a number of works on calendrics. In 1842, he was named shomotsu bugyô (Documents Magistrate).
Studying Rangaku and English, Shibukawa came to be assigned by the shogunate to a variety of other tasks; in 1844, he translated a letter to the shogun from King Willem II of the Netherlands.
Shibukawa played a role in drafting or implementing the Tenpô Reforms alongside Mizuno Tadakuni, Torii Yôzô, and Gotô San'emon, but following Tadakuni's death, Shibukawa was exiled in 1845 to Usuki han in Kyushu. He died there on 1851/7/25, and the shogunate dispatched an official to investigate the circumstances of his death.