Named in memory of Shibukawa Shunkai (1639–11715), who was an expert on the calendar. Born into a family of “go” teachers in Kyoto, he studied the calendar system and astronomy and found that the lunisolar calendar, which had been used without any modification for more than 800 years after it was imported from China, did not match observations. He revised the calendar using observations of the sun and moon, and his calendar system was adopted by the Tokugawa government in 1684. He was then nominated as “The Astronomer”, which was a new title for him. The title was inherited by his family. The Tokugawa government also established the observatory with Shunkai as the director. (M 34352) _ _.