In response to growing Chinese incursions into Japanese airspace, the Japan Air Self-Defense Force has established a new permanent squadron of Northrop Grumman Hawkeye airborne early-warning aircraft on the island of Okinawa. The ministry of defense has also broken ground for a new radar site on Japan’s most westerly island, Yonaguni.

Since unilaterally imposing its East China Sea air defense identification zone, which partly overlaps that of Japan, China has repeatedly flown aircraft into the area, in turn requiring Japanese fighters to scramble. The number of incursions is increasing steadily: in the 12 months up to the end of March there were 415 scrambles, as opposed to 306 last year.

For better surveillance capability over its southern waters, Japan has established 603 Hiko-tai (squadron) at Naha air base on Okinawa to operate four Northrop Grumman E-2C Hawkeyes. The aircraft were previously flown by 601 Hiko-tai, part of the Hiko Kaikai Kanshigun (air warning surveillance group) located at Misawa in the northern part of Japan. That unit previously undertook deployments to Naha, but the presence has now been turned into a permanent unit, which will have up to 130 personnel assigned by next year.

During the ceremony to inaugurate the Naha Hawkeye squadron on April 20, Japan’s defense minister, Itsunori Onodera, warned that China’s continual attempts to “change the status quo by force and threaten the rule of law could trigger emergencies.” He later told reporters: “The squadron was newly established to firmly defend our country’s territorial land, sea and air.” On the previous day Onodera had attended another ceremony, on Yonaguni island, to mark the beginning of construction of a radar site to monitor air and sea traffic. The island lies to the southwest of the disputed Senkaku/Diaoyu islands.

Japan took delivery of 13 E-2C Hawkeyes beginning in 1982. Nine of the fleet are retained by 601 Hiko-tai at Misawa. The JASDF also operates four Boeing E-767s in the AEW role, which fly from Hamamatsu with 602 Hiko-tai as part of the air warning surveillance group.

As well as its new Hawkeye unit, Naha is home to 204 Hiko-tai, which flies Boeing/Mitsubishi F-15J Eagles. For many years the Okinawa base, headquarters to the Southwest air division, was traditionally the “poor relation” when it came to new equipment, usually operating the JASDF’s oldest fighter types. With the threat focus shifting away from Russia to the north to China in the west, that changed in 2009 when the Naha-based F-4EJ Phantom unit swapped places with a mainland unit flying the more capable Eagle.