Project Blue Book Case #1340. On June 25, 1952, an unidentified object was observed over Tokyo, Japan — the world's largest metropolitan area and the center of the American occupation. With a population exceeding eight million, Tokyo's airspace was busy with military flights from Yokota, Johnson, and Tachikawa air bases, as well as growing civilian traffic. The Korean War made Tokyo the primary rear-area command center for UN forces.
June 25, 1952, was the second anniversary of the North Korean invasion that started the Korean War. The case was classified "Unknown."