The Hokkaido University Faculty of Humanities and Human Sciences Humanities Café Planning Working Group will be holding the 35th Hokkaido University Literature Café, “Ancient ‘midnight snacks’ are stories about solar eclipses – Tracing the Japanese calendar with a calendar expert” on July 26th.

The theme of the 35th Hokkaido University Literature Cafe is "The History of the Japanese Calendar."

The current calendar in Japan is a solar calendar based on 365 days a year. We have been living under the solar calendar for about 150 years since the Meiji calendar reform in 1873. In contrast, the calendar used from ancient times until the Meiji calendar reform was a lunisolar calendar, which determines dates based on the phases of the moon and the annual motion of the sun. In other words, in the past, only experts who could estimate the motion of the moon and the sun could create calendars.

For this reason, the Imperial Court has had specialists known as rekihakase (calendar doctors) since ancient times, who produced calendars every year. Calendars also included various astronomical phenomena, but one of the most difficult tasks was predicting solar eclipses. This article introduces the ancient calendar-making process, focusing on the calendar doctors who were so troubled by this task that they even invented something called a "midnight snack."

For more information, please click here. *You will be redirected to the Hokkaido University Faculty of Humanities and Human Sciences website.