Chitose Air Base, Japan, September 1957September 1957

On September 1, 1957, an airman stationed at Chitose Air Base in Japan photographed what he believed was an unidentified flying object. The airman was taking pictures of flagpoles at the base around 0430 or 0530 (early morning, somewhere between 4:30 and 5:30 a.m.) when he noticed a dark, shadowy object moving from left to right across his camera viewfinder. The sighting lasted only two to three seconds, the time it took to snap the photograph. When the airman lowered the camera to look at the object with his naked eye, it had already vanished.

Officials at Chitose Air Base were initially hopeful about confirming the sighting. The ground-controlled approach radar unit at the base, the aircraft control and warning units, and other facilities were asked whether they had detected anything unusual in the area during the relevant time period. All reported negative results. No radar tracks matched the report, and no other witnesses came forward to corroborate what the airman had seen.

Air Force photo analysts examined the negative and print carefully. They concluded that the dark blotch on the photograph was not an actual object in the sky. Instead, the analysis found that during film development, part of the film had made contact with something in the developing tank or with another layer of film. This prevented the chemical development process from occurring properly in that area, creating a dark mark when the print was made. The analysts noted that a truly dark flying object of the described distance would have shown more detail and a sharper outline than what appeared on the film.

The case file was marked "unknown" by the Air Force, though the photographic evidence had been explained as a development artifact rather than an actual sighting. The full case file is reproduced below as held by the National Archives in 13 pages.