Iwo Jima, Japan [EPA Yonhap News]

Japan is planning to expand its Air Defense Identification Zone (ADIZ) to cover Pacific islands and upgrade Self-Defense Force base facilities, with an eye on China's increasing military activities in the Pacific, the Asahi Shimbun reported on the 4th.

An ADIZ is an imaginary line established to identify aerial threats early and differs from territorial airspace under international law. Japan scrambles fighter jets and other aircraft to respond to aircraft it deems to pose a threat of airspace violation upon entering its ADIZ.

Japan's current ADIZ is based on the one established by the U.S. military in the 1950s, which did not include the airspace above the Ogasawara Islands, Pacific islands south of Honshu, at the time.

In response, the Ministry of Defense is considering incorporating the airspace over the Ogasawara Islands into its ADIZ.

Asahi explained, "This is intended to strengthen the Self-Defense Forces' surveillance posture, considering China's active military operations in the Pacific."

However, the newspaper pointed out that if the Japanese government includes the airspace over the Ogasawara Islands in its ADIZ, it could heighten military tensions with China.

When Japan expanded its ADIZ in 2010 to include waters near Yonaguni Island in Okinawa Prefecture, an island near Taiwan, Taiwan expressed its displeasure.

Furthermore, when China established its ADIZ in 2013 over the East China Sea, including the airspace above the Senkaku Islands (known as Diaoyu Islands in China), the United States and Japan criticized the move.

While the airspace over the Ogasawara Islands does not overlap with other countries' ADIZs, potentially leading to less significant backlash from neighboring countries, frequent scrambles of SDF aircraft in response to movements of Chinese military aircraft after Japan establishes its ADIZ could lead to heightened confrontation between Japan and China.

In addition, Asahi analyzed that expanding the ADIZ would require the installation of radar in the area and changes to fighter jet deployments.

The Japanese government's initial plan is to fill surveillance gaps in its airspace using early warning and control aircraft equipped with radar.

Separately, Japan plans to begin surveys for the maintenance of runway and port facilities on Iwo Jima (硫黃島), an island in the Ogasawara Islands, and to strengthen its vigilance and surveillance systems.

In this regard, measures such as installing a pier-like structure to accommodate large vessels and permanently deploying SDF fighter jets to counter Chinese military aircraft are being discussed.

The Ministry of Defense will establish a "Pacific Defense Planning Office" next month and plans to include a policy of "strengthening Pacific defense" in the three security documents to be revised within the year.

Regarding the reinforcement of the SDF base on Iwo Jima, Asahi reported that challenges include potential difficulties in facility maintenance due to volcanic activity and the need to coordinate with families of the deceased from World War II, whose remains are still present on the island.