involved 110 aircraft, later reduced to 96, which were upgraded with APG-66 radar, 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-1s which were too few in number and lacked range, and the P-3Cs which were too slow, even if well-armed with Harpoon missiles. The F-4EJ Kai upgrade added several other air-to-surface weapons to the F-4, including bombs and rockets. Fifteen 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 first flew on 17 July 1984, and first entered service 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/shootdown capability. The central computer was updated, as well as the J/APR-6 homing and warning system, IFF system and the inertial navigation unit. The first F-4EJ Kai aircraft were delivered to the 306th Hikōtai at Komatsu, but within a few years they were replaced by F-15Js. In April 1994, the F-4EJ strength was reduced to three squadrons: 8 (Misawa), 301 (Nyutabaru) and 302 (Naha, Okinawa). The 501st at that time operated the RF-4E. Over time the F-4s and F-1s are being replaced with the new Mitsubishi F-2, an enlarged development of the F-16 developed jointly with Lockheed Martin. Units Japan Air Self-Defense Force Air Development and Test Wing (1971–2021) 8th Hikōtai (1997–2009) 301st Hikōtai (1973–2020) 302nd Hikōtai (1974–2019) 303rd Hikōtai (1976–1987) 304th Hikōtai (1977–1990) 305th Hikōtai (1978–1993) 306th Hikōtai (1981–1997) 501st Hikōtai (1974–2020) South Korea Republic of Korea Air Force, ROKAF was supplied with F-4s in the late 1960s, due to ongoing tension with North Korea. Seoul ordered 18 ex-USAF F-4Ds, which were quickly delivered under the Peace Spectator program. They served with the 110th TFS, 11th Fighter Wing based at Daegu. In 1972 another 18 were delivered from the USAF 3rd TFW (Tactical Fighter Wing), in exchange for which South Korea delivered 36 Northrop F-5As to South Vietnam. Several more F-4s were delivered in the following years, with the last batch delivered in 1987–88. These were equipped with