In 1989, it had been quite some time since independent filmmaker Sekine Hiroyuki had produced a film. But as he passed in front of some ruins one day, he decided to break that silence with a new work. This became the series Tokyo Walk ("Tokyo Sanpo"). Having formed a gradual attachment to the ruins left stranded in the middle of Tokyo and other big cities, Sekine decided to make such ruins the subject of his films. Thus he started to produce films again. In Ruins of Roppongi, acclaimed as masterpiece of independent film, Sekine uses a Canon single 8 camera 518SV to film vestiges of old residences left on the site of the old Philippine Embassy. Broken glass, old abandoned chairs, and the discovery of 16mm film enriches this work.

U. O. stands for "Unidentified Object". The film is shot on the site of the old US base in Sengen-cho, Fuchu City, with its weather-beaten radars and surrounding greenery. Sekine intrudes on these ruins, using the imaginative motif of what the discarded radars might still pick up. Factories, warehouses, offices, markets and dormitories dot the large piece of land, coexisting with the surrounding greenery.