The origin of U.S. Navy Information Operations Command, Misawa dates back to December 1945 when RM1 Brillhart was Petty Officer in Charge of COMMSUPACT in Ohminato, Japan. In April 1946, COMMSUPACT operations moved to Yokosuka, Japan. Twelve years later operations were relocated to Kamiseya, Japan with CDR C. M. Smith as head of NAVSECGRU Department NAVCOMMSTA Kamiseya. U. S. Naval Security Group Activity, Kamiseya was established on 15 January 1960, under the command of CAPT E. W. Knepper. The activity remained on the Kanto Plain until March 1971 when most functions of NIOC Kamiseya were moved to Misawa. On 1 July 1971, U.S. Navy Information Operations Command, Misawa was commissioned under the command of CAPT G. P. March.
On April 15, 1969, two North Korean MiGs shot down a Navy EC-121 in an unprovoked attack. On board the aircraft were thirty-one of our Shipmates, thirty Sailors and one Marine, who all perished.
The crew took off from Naval Air Station Atsugi at 0700 that morning and headed for the Sea of Japan. Nearly six hours into a routine mission, the crew got word of the presence of North Korean fighters. After identifying the fighters and acknowledging the impending intercept, the EC-121 aborted the mission and turned to head home. The EC-121 is a large, slow, propeller-driven, unarmed aircraft and despite its attempt to avoid the threat, the much faster North Korean fighters were able to intercept the EC-121. At 1347 local time, the two tracks met and the EC-121 disappeared from the radar screen and was never heard from again.