ACUFO:

N - 1945.04.03, 1817Z - Near land's end Tokyo Bay.

B-29, 9000 feet, saw a ball of fire about the size of a basket ball. Evasive action not effective after following the aircraft for 6 minutes it turned back toward the coast. (One crew member thought he saw a navigation light on a wing.) (Report of Operation 3-4 April 1945, HQ 21st Bomber Command, 500th Bombardment Group History)

On April 3 and 4, 1945, 61(30) of the 115 B-29s dispatched from the 73rd attack an aircraft plant at Tachikawa and 49 B-29s attack the Kawasaki urban area. One (I) 8-29 is lost.

NOTE: There were sightings of strange objects on this mission:

[... other cases...]

4. B-29 at 9,000 feet, saw a ball of fire about the size of a basketball. Evasive action not effective. After following the aircraft for 6 minutes it turned back toward the coast.

April 3, 1945

Tokyo Bay area, Japan

At 1817 (zulu), the pilot and crew of a B-29 flying at 9,000 ft high, observed a ball of fire, size of a basket ball. Evasive actions were not effective. After following the aircraft for 6 minutes, it turned back toward the coast. One crew member thought that he saw a navigation light on a wing.

Sources: Project 1947, Jan Aldrich / Report of operation 3-4 April 1945, HQ 21st Bomber Command.

The [XII Tactical Air Command's Intelligence Information Bulletin] bulletin for June 4, 1945, discusses reports from Japan:

DON'T LOOK NOW, BUT -:

Mention has previously been made in these pages to the existence of German airborne controlled missiles Hs.298, Hs.293, X4 and Hs.117. Many reports have been received from Bomber Command crews of flaming missiles being directed at, and sometimes following the aircraft, suggesting the use of remote control and/or homing devices. It is known that the Germans kept their Japanese Allies informed of technical developments and the following report, taken verbatim from Headquarters, U. S. A. F. P. O. A. G.2 Periodic Report No. 67, further suggests that the Japanese are using similar weapons to those reported by our own crews:

“During the course of a raid by Super-Fortresses on the Tachikawa aircraft plant, and the industrial area of Kawasaki, both in the Tokyo area, a number of Super-Fortresses reported having been followed or pursued by “red balls of fire” described as being approximately the size of a basketball with a phosphorescent glow. Some were reported to have tails of blinking light. These “balls” appeared generally out of nowhere, only one having been seen to ascend from a relatively low altitude to the rear of a B-29. No accurate estimate could be reached as to the distance between the balls and the B-29's. No amount of evasion of the most violent nature succeeded in shaking the balls. They succeeded in following the Super-Fortresses through rapid changes of altitude and speed and sharp turns, and held B-29s' courses through clouds. One B-29 reported outdistancing a ball only by accelerating to 295 mph, after which the pursuing ball turned around and headed back to land.

Individual pursuits lasted as long as six minutes, and one ball followed a Super-Fortress 30 miles out to sea. The origin of the balls is not known. Indication points to some form of radio-direction, either from the ground or following enemy aircraft. The apparent objective of the balls, no doubt, is destruction of the Super-Fortresses by contact. Both interception and AA [anti-aircraft] have proved entirely ineffective, the enemy has apparently developed a new weapon with which to attempt countering our thrusts.”