Jōkyō calendar

The Jōkyō-reki system was developed and explained by Shibukawa Shunkai.^[3] He recognized that the length of the solar year is 365.2417 days.^[1]

Shibukawa discovered errors in the traditional Chinese calendar, the Senmyō calendar, which had been in use for 800 years.^[3]

• Japanese calendar
• Sexagenary cycle
• Jōkyō

• National Diet Library, "The Japanese Calendar" -- historical overview plus illustrative images from library's collection