From みんなのきもち Minna-no-Kimochi’s YouTube page:

This event was held on privately owned land completely surrounded by the taxiways of Runway B at Narita International Airport. The site traces its origins to the Sanrizuka struggle of the 1960s-70s and remains one of the few privately owned facilities that still retains independent title within the airport grounds. As a symbol of more than half a century of resistance to land expropriation, it presents a distinctive landscape in which wide-body aircraft take off and land on all sides.

For ease of reference, our announcements and this release use the shorthand “at Narita Airport” when describing the location. This choice is purely for clarity and in no way meant to diminish the site’s historical significance. On the contrary, we employ this convenient wording precisely to respect the cultural and social value of this exceptional tract of land and to safeguard the conditions that allow activities here to continue.

The actual venue name and exact address are not disclosed because (1) we wish to protect the facility’s privacy, and (2) the event is a closed gathering operated exclusively for invited participants.