A radar lock-on, used to guide missiles, is considered a serious escalation compared with routine surveillance, an expert said.

TOKYO (AP) — Japan and Australia urged calm on Sunday after Chinese military aircraft locked radar on Japanese fighter jets, a month after the Japanese leader’s recent remarks on Taiwan that stirred tensions between Tokyo and Beijing.

China and Japan ties, already frayed by comments made by Prime Minister Sanae Takaichi on Taiwan, came under further strain at the weekend after a Chinese fighter aircraft trained fire-control radar on Japanese military jets for the first time.

The Japanese government is taking uncomfortable steps to prepare its citizens for a possible future war that its military would not be able to avoid.

The 15-year effort by Japan is a model for countries now scrambling to reduce their dependence on Beijing’s critical metals.

A Chinese Foreign Ministry spokesperson has repeated the country's claim over the radar targeting issue with Japan.

No end in sight to spat between Japan and China over Taiwan, as neither Tokyo nor Beijing shows signs of backing down.

Diplomatic crises often change the stakes for each, and for the Japanese, the consequences of this crisis are multifaceted. Japan’s new prime minister, Takaichi Sanae, was the initial focal point. As the Washington Post editorial board aptly noted,

Japan's Defense Minister Koizumi Shinjiro has again expressed concern over Chinese military aircraft directing radar at Japanese Air Self-Defense Force fighter jets over international waters off Okinawa's main island in southern Japan on Saturday.