Chinese Aircraft Illuminate Two JASDF Jets

 Chinese Aircraft Lock their Radar on Two JASDF Jets

By Takuya Nishimura, Senior Fellow,  Asia Policy Point
Former editorial writer for the Hokkaido Shimbun
You can find his blog, J Update here.
December 8, 2025

Japan’s Minister of Defense Shinjiro Koizumi announced on December 7 that one or two Chinese fighter jets, the previous day, had intermittently illuminated their radar onto two of Japan’s Air Self-Defense Force fighter jets in separate incidents near the Okinawa prefecture. Tokyo immediately protested, although Beijing denied the action. While China’s motivations are unclear so far, it is believed that this provocation reflects China’s frustration with Prime Minister Sanae Takaichi’s remarks last month that her government would view Chinese action on Taiwan – the “Taiwan contingency” – as a threat to Japan.
 
Koizumi’s report came in an unusual post-midnight Ministry of Defense press conference at 2 a.m. Sunday morning. Koizumi reported that two ASDF F-15 fighter jets were exposed to radar directed by J-15 Chinese warcraft twice on the afternoon of December 6. The Japanese jets were flying over international waters southeast of the Okinawa Main Island. Chinese jets were installed on an aircraft carrier, Liaoning, which was in an exercise nearby, also in international waters.
 
A fighter jet has two kinds of radar: fire-control radar and search radar. Fire-control radar is a radio wave to determine the precise location, flying speed, and direction of a target to guide weapons to the target. Search radar is used to find any aircraft, including commercial ones, within a wide area. The radar used by Chinese military aircraft was reportedly fire-control radar.
 
Locking fire-control radar on a target may be a sign that the aircraft can be shot down, metaphorically the same as putting a finger on trigger of gun. A radar lock is recognized as potentially leading into battle. “It was a dangerous activity which went beyond necessity for the safe aviation of an aircraft and extremely regrettable,” said Koizumi. “It was extremely regrettable. We will deal with this issue resolutely and calmly,” Prime Minister Takaichi said.
 
Beijing dismissed Japan’s argument as inconsistent with the facts. “We sternly urge the Japanese side to immediately cease its slanderous and defamatory acts against China and strictly discipline its front-line operations,” said a spokesperson for the PLA Navy, Wang Xuemeng. The Chinese Ministry of Foreign Affairs argued that activating search radar during flight training is commonly done by carrier-based aircrafts of all countries, indicating that the radar illuminated onto JASDF aircraft was not fire-control radar, but search radar.
 
Japan has not determined whether this radar incident was related to Takaichi’s comment on the Taiwan contingency. The significance of her comment is that Chinese action on Taiwan would trigger Japan’s authority to exercise its right to collective self-defense, including necessary military action. While China has been escalating its response to her comment through economic and cultural activities, launching fire-control radar would mark the first major military event in this bilateral row.
 
When the Japanese government purchased the Senkaku Islands from a Japanese owner in 2012, China responded intensively with near-constant incursions into the territorial water around the Senkakus. In 2013, a Chinese frigate locked fire-control radar on a destroyer of the Japan Maritime Self-Defense Force, the only disclosed example of China’s use of fire-control radar before last Saturday. 
 
China has been enlarging its territorial advances toward Japan in recent years. Chinese military aircraft for the first time invaded Japan’s territory offshore of Nagasaki in August 2024. A Chinese Coast Guard helicopter breached territorial waters close to the Senkaku Islands in May 2025. Thus, China may be taking advantage of Takaichi’s comment to step up its pre-existing military pressure on Japan.
 
China argues that its forces were in a naval exercise in neutral water, a not uncommon event for maritime nations. The radar incident occurred, according to the Chinese, because the Japanese fighter jets had scrambled to deter a Chinese fighter jet from a Chinese aircraft carrier. Yomiuri Shimbun reported the possibility that Chinese aircraft carriers are constantly present in the sea around Japan, including the Liaoning, the Shandong and the Fujian. China also is engaged more frequently in joint exercises with Russia around Japan.
 
Japan is strengthening its efforts to gain support from like-minded countries. The Defense ministers of Japan and Australia met in Tokyo on the day after the radar illumination. They announced the establishment of a Framework of Strategic Defense Coordination and welcomed the progress on Australia’s introduction of a Mogami-class frigate. “We are deeply concerned by the actions of China in the last 24 hours,” the Australian defense minister, Richard Marles, said at the press conference.
 
Although Japan and China have established a hotline between them to avoid an accidental conflict, the countries did not use the line during the radar illumination event – indeed, there is no evidence that it has ever been used. Japan thus has no viable channel to maintain a security dialogue with China. Japan likely expects the United States to communicate on its behalf with China, which at this writing does not appear to have happened. Takaichi was delighted with President Donald Trump when, during her November call with him, he invited her to call him anytime she wants. Tokyo is watching Trump’s actions on this matter but has seen nothing so far.