Actually just five Air Forces operated the F-4E: Greece, Turkey, Iran, South Korea and Japan. Japan selected the F-4 Phantom II as its new fighter at the end of the 1960s. On 1 November 1968, this choice was made public and Japan became one of the few countries that license-produced this aircraft. The Nihon Koku Jietai (Japan Air Self-Defense Force, JASDF) received a total of 154 F-4EJ and RF-4Es. While the F-4EJs were built almost entirely by Mitsubishi Heavy Industries, the RF-4Es were bought directly from McDonnell-Douglas.
Due to US restrictions that did not allowed Japan to develop an air-to-ground ordnance, the F-4EJs were delivered/produced without the AN/AJB-7 bombing computer system and also did not have an air-refueling probe or receptacle. In service F-4EJs replaced the JASDF’s fleet of Locheed F-104J Starfighter.
McDonnell Douglas built the two prototype F-4EJs, which first flew on 14 January 1971. The next 11 aircraft were assembled in Japan and the first Japanese-built example flew on 12 May 1972. Mitsubishi built all the EJs over the next nine years and the production ended with 127th F-4EJ, on 20 May 1981. This was the last F-4 built in the world.
Fourteen RF-4Es were delivered between November 1974 and June 1975. These were similar to the RF-4C, but, as for the F-4EJs, Japanese-built Radar Warning Receivers and other equipment were substituted to replace equipment which was not released for export to Japan.
The F-4EJ entered service with the JASDF in August 1972 with a total of six Hikōtai (“Squadrons”) operating the aircraft: the 301, 302, 303, 304, 305 and 306th. The RF-4EJ equipped the 501st, that had previously operated one of the less-well-known Sabre models, the RF-86F. The first Squadron (Hikotai) that was equipped with F-4EJ was the 301 in Hyakuri.
301 Squadron for all the Japanese Phantom era was responsable for the trainig of the new Phantom pilots. The first real Alfa Scramble for 301 Hikotai took place on February 1979 when two Phantom intercepted a Soviet Tu-95 Bear. 302 Hikotai was estabilished on 18th July 1974 and become operative in 1975 and it was based in Chitose, in the northern part of Japan and in 1985 it was relocated in Naha/Okinawa air base.
303 Hikotai recieved its Phantoms on 1976, in Komatsu air base. Due to the base position, in front of Noth Korea and URSS, the 303 Phantoms were highly active in QRA missions. In 1991 the 303 Hikotai began its conversion to the F-15J. Japanese procurement involved small, multi-year orders, which made for slow production of small batches ordered every year. As of 2019, Japan has a fleet of around 30 F-4s currently in service.
To upgrade the Phantom fleet the JASDF planned the F-4EJ Kai (Japanese for “modified”) program. This involved 110 aircraft, later reduced to 96, which were upgraded with APG-66 radar, which is smaller and lighter than the original APQ-120, but possessed extended operational ground attack capabilities and most importantly, ASM-1 or ASM-2 anti-ship missiles (two mounted under the wings). This boosted their capabilities in the anti-shipping role; filling in for the indigenous Mitsubishi F-1 which were too few in number and lacked range, and the P-3C which were too slow, even if well-armed with Harpoon missiles.
The Kai program included even a new HUD, IFF system Hazeltine AN/APZ-79, inertial navigation unit LN-39, new UHF antenna. The F-4EJ Kai upgrade added several other air-to-surface weapons to the F-4, including bombs and rockets and the possiblity to use the AIM-7E/F Sparrow and AIM 9L/P Sidewinder
RF-4Es were upgraded to RF-4 Kai standard with AN/APQ-172 TFR radar, and the J/APR-2 RWR was replaced with the J/APR-5; both Japanese-designed systems. Seventeen F-4EJs were also converted to RF-4EJ configuration, which, while mounting no internal cameras, carried podded reconnaissance equipment. Among the systems installed were TACER (electronic reconnaissance pod with datalink), TAC (pod with KS-135A and KS-95B cameras), D-500UR IR detection system, and the LOROP pod (with a KS-146B camera).
The F-4EJ Kai (upgraded)first flew on 17 July 1984, and first F-4EJ Kai was delivered on 24 November 1989 to the JASDF 306th Squadron. It was fitted the smaller and more lightweight AN/APG-66J pulse Doppler radar and a heads-up display resulting in a lookdown/shotdown capability. The central computer was updated, as well as the J/APR-6 homing and warning system, IFF system and the inertial navigation unit.
302 Hikotai have been converted on F-35 on March 2019, moving to Misawa air base, and nowadays Japan has only two Phantom Squadrons, 301 equipped with F-4EJ Kai and 501 equipped with RF-4E and RF-4EJ Kai, both based in Hyakuri air base. The program to replace the Phantom with the new F-35 is going to became real in March 2021, when the last Samurai will stop to serve in the Japanese sky.