Tachi (sword) named Koinmeitachi, dated 570AD found in Fukuoka, Kyushu.

Itoshima is a nice little region found to the west of modern Fukuoka city. It is still relatively underdeveloped and rural, which I think is great. Although, as Fukuoka city has expanded and people are looking to get out of the hustle and bustle of city life, many are moving to Itoshima.

One major change to the town of Motooka, Itoshima is the new Kyushu University Ito campus which celebrated its opening in 2018. The university takes up a very large area of Itoshima (272 hectares) and can easily be seen from the surrounding areas. During construction many ancient kofun (tombs) were uncovered. I may look into doing a blog about all of the findings from the tombs, but for now I would like to talk about one of the best finds in Japanese history.

The Koinmeitachi was excavated in 2011. Tachi in this case meaning long sword (over 60cm), not to be confused with ancient straight swords called Chokuto. It was found in the Motooka G6 Kofun which is dated at the end of the Kofun period in the 6th century. The tachi is made of iron, 75cm long and believed to have been made in 570AD. The original sword and a replica was on show and I was lucky enough to go see it.

Inlaid in pure gold are 19 characters in a style resembling Chinese clerical script. The characters indicate that the tachi was made on the day of Koin. The 6th day of the first month of the year Koin. Koin is the 27th term in the Chinese sexagenery cycle. This is interesting as it was thought, at that time in Japan, the Genka Lunisolar calendar was used. If we cross reference this time period covered by this calendar, the year of Koin on which the day of Koin falls on the 6th day of the month corresponds to the year 570AD on the western calendar. As a result of this find, the date inscription may be the oldest evidence of calendar use in Japan.

All information is from the Fukuoka Archaeological Centre, Itazuke, Hakata and the Fukuoka City Economic and Tourism Culture Centre. I also used information from Koinmeitachi, a publication from the Fukuoka City Archaeology Center dated 22nd March 2019.

My photos.


    1. Hi Tom. Good question. The uni and museums that worked on this believe in was made in Japan, not due to the metals used but because of the dating system used on the sword. I think previous swords to this were brought into Japan from Korea and China.

      Liked by 1 person

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