Tensions between Japan and China escalated over the weekend after Tokyo accused Chinese carrier-based fighter jets of locking their radar onto Japan Air Self-Defense Force (JASDF) aircraft over international waters near Okinawa.

Beijing quickly rejected the allegation, accusing Tokyo of provoking and endangering Chinese training activities. The exchange has fueled concern over the growing risk of an unexpected encounter leading to an armed clash in increasingly tense air and sea spaces around Japan and Taiwan.

Japan’s Ministry of Defense said December 7 that Chinese J-15 aircraft launched from the aircraft carrier Liaoning intermittently locked their radar onto JASDF F-15s in two separate incidents on December 6. It was the first time Tokyo had publicly disclosed a radar lock-on incident directed at Japanese fighter jets by Chinese military aircraft.

Defense Minister Koizumi Shinjiro held an emergency news conference at 2 a.m. on December 7, calling the radar lock-ons “extremely regrettable” and “dangerous,” saying the actions exceeded what is required for safe flight operations.

The incidents occurred during a particularly rocky patch for China-Japan relations. Tensions have sharply escalated following Prime Minister Takaichi Sanae’s November 7 comments indicating Japan might become militarily involved in a potential Taiwan contingency.

The ministry said the first incident happened between 4:32 p.m. and 4:35 p.m. on December 6, when a J-15 fighter jet launched from the Liaoning intermittently illuminated its radar toward a JASDF F-15 conducting an intercept mission southeast of Okinawa. A second J-15 carried out a similar radar lock-on against another F-15 between 6:37 p.m. and 7:08 p.m. the same day. No damage or injuries were reported.

Fighter aircraft radars typically operate in two modes: a wide-area search mode used to detect multiple........

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