Show Summary Details

Page of

Printed from Oxford Research Encyclopedias, Planetary Science. Under the terms of the licence agreement, an individual user may print out a single article for personal use (for details see Privacy Policy and Legal Notice).

date: 27 January 2023

Records of Planetary Observations in Ancient Japan Before the 11th Centurylocked

Records of Planetary Observations in Ancient Japan Before the 11th Centurylocked

  • Kiyotaka TanikawaKiyotaka TanikawaNational Astronomical Observatory of Japan
  •  and Mitsuru SômaMitsuru SômaNational Astronomical Observatory of Japan


The records of planetary observations in Japan in the 7th century ad are treated separately from other records because they are written in the Nihongi. It is known that Japanese observational astronomy was recorded in the 7th century ad, but astronomy in Japan did not evolve straightforward in that century. There are thirty-one records that exist from that time, including four records on the Moon and planets. Correspondingly, a new interpretation of Japanese ancient history has been proposed. For the 8th, 9th, and 10th centuries, records have been compiled on the relative motion of the Moon and the planets, the motion of planets in the constellations, and stars seen in the daytime, as stated in Japanese recorded history. These records are written in Chinese, as in the case of the Nihongi, but have been translated into English. The orbits of the Moon and planets have been calculated using the NASA Jet Propulsion Laboratory (JPL) development ephemeris (DE) in order to confirm the validity of the records. The numbers of records and observations are not the same because one record may contain multiple observations. The accuracy of individual observations is discussed.


  • History of Ideas about Planets and Planetary Systems
  • Solar System Dynamics and Orbital Structure

You do not currently have access to this article


Please login to access the full content.


Access to the full content requires a subscription