Minamitorishima, Ogasawara Village, Tokyo. (©Sankei by Kenji Suzuki)
As part of efforts to strengthen surveillance and monitoring along the Pacific coast, the Japanese government is considering establishing an Air Defense Identification Zone (ADIZ) over the Ogasawara Islands, located South of Tokyo.
An ADIZ is airspace established beyond a country's territorial airspace — generally extending past the approximately 22-kilometer limit from the coastline — at each nation's discretion.
It is designed to enable early responses before an aircraft enters sovereign airspace. In Japan's case, when an unidentified aircraft enters the zone, the Self-Defense Forces scramble fighter jets to carry out airspace violation response measures.
Ogasawara's Blind Spot
Japan's ADIZ is based on airspace originally designated by the United States military for air traffic control purposes after World War II. But because the skies over the Ogasawara Islands were not included in those US-defined zones, leaving surveillance and monitoring in the area comparatively weak.
As Chinese naval aircraft carriers push deeper into the Pacific, the likelihood of carrier-based fighter jets encroaching on the airspace over the Ogasawara Islands is increasing.
In fact, tensions have already risen. In December 2025, a Chinese military aircraft launched from the carrier Liaoning reportedly locked its radar onto a Japan Self-Defense Forces jet that had scrambled in response over international waters southeast of Okinawa's main island.
Yet even if an ADIZ were established over the Ogasawara Islands, the operation of scrambling Self-Defense Forces aircraft would remain a key challenge.
If jets are dispatched from distant air bases, they would require refueling and logistical support. This is why strengthening base functions on Iwo Jima is becoming important, with some proposals even calling for the permanent stationing of SDF aircraft there.
"To establish an Air Defense Identification Zone, it is essential to have the capability to operate Self-Defense Forces aircraft from Iwo Jima," a Defense Ministry official said. "Expanding the posture, including permanent deployment, would come afterward."
Pacific Wake-Up Call
Kunio Orita, a retired lieutenant general of the Japan Air Self-Defense Force, said, "Since the end of World War II, the Air Self-Defense Force's air defense posture has been oriented primarily toward the north, with the Soviet Union as its main focus."
"With little perceived threat on the Pacific side and limited budgets," he added, "radar sites were not sufficiently deployed there, rendering the area effectively exposed."
In recent years, however, Chinese naval carriers have become more active in the Pacific, making the establishment of an ADIZ over these coverage gaps an urgent priority.
"It is anomalous that Japan has not established an ADIZ over parts of its own territory," Orita, also a special professor at Reitaku University, said. "As Chinese fighter jets increasingly operate with impunity between the First and Second Island Chains, the issue has become one of safeguarding the archipelago's territorial sovereignty."
Iwo Jima as Anchor
"What is needed first is an effective air defense response capability," the former general said.
He noted that Iwo Jima, with its 2,600-meter runway that allows fighter jets to take off and land freely, would be developed into an operational base.
"By upgrading infrastructure such as port facilities and establishing systems for supplying ammunition and fuel, fighters deployed from bases on the Japanese mainland would be able to maintain a standby posture," he said.
Japan's ADIZ is intended to prevent violations of its airspace, not to restrict freedom of flight, Orita added. "While China may object to any new designation, establishing such a zone over one's own territory is a normal and internationally accepted practice."
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Author: Taisuke Nanjo, The Sankei Shimbun
(Read this article in Japanese)
