Excavations at the former site of the British Embᴀssy in Tokyo’s Chiyoda Ward have revealed the remains of a Yayoi period settlement dating between the 9th century BCE and the 3rd century CE.

An archeological dig site is seen at a site formerly a part of the British Embᴀssy grounds in Tokyo’s Chiyoda Ward. Credit: Mainichi/Akihiro Kawakami

The site, now slated for condominium development by Mitsubishi Estate Residence and partners, has unveiled 28 pit houses, including some from the even older Jomon period.

Chiyoda Ward officials, in discussions with Mainichi Shimbun, disclosed that the ongoing archaeological survey, set to conclude in March 2024, has uncovered dwellings from the 1st to 2nd centuries, as well as Jomon period structures, complete with discarded mollusk shells. Noteworthy findings include Yayoi and Jomon earthenware, a wooden water pipe, a well, and an early modern period cellar.

Meiji University archaeology professor Hideshi Ishikawa expressed surprise at the discovery. He remarked, “Few settlements from the first half of the late Yayoi period with this many dwellings have been discovered in the southern Kanto region.”

Ruins of a pit dwelling from the Yayoi period excavated at a site formerly a part of the British Embᴀssy grounds and now slated to become a condominium in Tokyo. Credit: Mainichi/Akihiro Kawakami

The Chiyoda government, while recognizing the significance of the ruins, currently does not plan to designate them as a nationally protected historic site. Instead, the intention is to document the findings before the land is backfilled for construction.

Attempts were made by Chiyoda’s government and Mitsubishi Estate to negotiate the preservation of at least a portion of the ruins, along with the possibility of holding an on-site information session for the public. However, these efforts were thwarted as the company’s consent could not be secured.

Mitsubishi Estate, which acquired the 9,259-square-meter parcel from the British government in April 2022, is spearheading the redevelopment project with other real estate enтιтies. Observers noted that the property had not been excavated since the Meiji Era (1868-1912), raising suspicions that ancient ruins might lie beneath the surface. An exploratory excavation in February, with the company’s consent, revealed the ancient settlement, prompting a construction postponement and the initiation of the survey in June.

The archaeological survey, covering approximately 7,700 square meters, is only halfway complete, leaving open the possibility of more discoveries. Mitsubishi Estate is bearing the cost of the survey, emphasizing compliance with laws and ordinances in consultation with administrative authorities.

While the Chiyoda government remains keen on the archaeological find, the lack of national historic site designation means that, as of now, the ruins may not receive the protective measures they deserve. The prevailing approach is to document the excavation details and re-cover the site, foregoing public briefings or preservation efforts.

Professor Ishikawa’s sentiments regarding the unique discovery echo the broader sentiment within the archaeological community. “These shed light on lifestyles at the time and are academically invaluable discoveries,” he remarked, emphasizing the rarity of such findings in the southern Kanto region.