Early unknown observed over Kyushu, Japan during the Project Sign era (1948)

Project Blue Book Case #218. On October 15, 1948, an unidentified object was observed over Kyushu, Japan — the southernmost of Japan's four main islands. As Case #218, this was an early entry from the Project Sign era, when the Air Force was genuinely investigating whether the objects might be extraterrestrial. Kyushu hosted multiple U.S. military installations, including Itazuke Air Base. The case was classified "Unknown."