Over the weekend, China announced a new Air Defense Identification Zone (ADIZ) across the East China Sea. Already at odds over their maritime boundary in the East China Sea, as well as over their sovereignty dispute over the Senkaku Islands (Diaoyu Islands for the Chinese) that sit offshore Okinawa, Beijing’s unilateral assertion of its control over the airspace above the sea will further upset the predictability of maritime relations in Northeast Asia. Coming too at a time when Beijing refuses to discuss these issues with Tokyo, China has vastly increased the unpredictability of the already growing interaction between Japanese and Chinese militaries.

On a map with coordinates that run north near South Korea’s Cheju Island and south to the area between Taiwan and Japan’s southernmost island of Yonaguni, the Ministry of National Defense announced the East China Sea Air Defense Identification Zone. Shen Jinke, spokesman for the PLA Air Force, announced two large aircraft carried out their first scouting mission under the new ADIZ, accompanied by early warning aircraft and fighter jets, on Saturday.

The Chinese ADIZ overlaps with existing ADIZs monitored by Japan as well as South Korea, and both governments have formally protested. Moreover, the Chinese announcement suggests that Beijing wants tough controls over transit through this region. The Chinese Ministry of National Defense called for all planes flying through its ADIZ to provide flight plan identification, radio identification, transponder identification, and logo identification. Most countries only require the submission of flight plans if the planes are traveling to their territory.

The Japanese government has refused to accept China’s new ADIZ. In the Upper House of parliament, Prime Minister Abe said this will “not have any effect on Japan,” and his Deputy Cabinet Secretary Katsunobu Kato told reporters that the ADIZ “unfairly violates the freedom of flight in airspace over the high seas.” On Monday, Foreign Minister Kishida contacted U.S. Ambassador to Japan Caroline Kennedy to ask for U.S. support in building a coalition of international opposition to China’s new ADIZ.

More importantly, China’s announcement runs jarringly counter to efforts to de-escalate tensions that erupted last summer over the Senkaku Islands. Since earlier this year, when a Chinese Jiangwei-II class frigate locked its fire-control radar on a Japanese Maritime Self-Defense Force destroyer Yudachi, the two nations have gradually reduced tensions in and around the disputed islands. A measure of predictability has characterized the interactions on the sea for much of this year, although renewed tensions seemed possible when Beijing sent a drone near the islands on September 9. Japan responded by stating it would shoot down any drones that entered its airspace.

Recently there were some signs of improvement in Sino-Japanese relations. While the Chinese government still refuses to organize a summit between China’s President Xi Jinping and Japan’s prime minister Abe Shinzo, working level talks continue between Japanese and Chinese governments. Moreover, track two discussions such as the Beijing-Tokyo Forum also resumed, including on the sensitive topic of maritime confidence building. Delegations of business leaders from both countries have also contributed to the sense of a lessening of tensions between the two countries. The Chairman of Keidanren, Hiromasa Yonekura, expressed his disappointment that Keidanren’s recent visit had no impact on Chinese attitudes towards Japan.

Beijing’s ADIZ announcement places Japan in a difficult spot. From Tokyo, the ADIZ looks like an effort to undermine Japan’s administrative control over the Senkaku Islands. China’s deployment of patrol ships to the Senkaku waters last year prompted a 24/7 presence by the Japan Coast Guard around the islands. Subsequent Chinese efforts to test Japan’s military preparedness in and around the disputed islands have also put pressure on the Japanese Self-Defense Force (SDF).

China’s decision to claim an expansive ADIZ across the East China Sea not only challenges its neighbors in Northeast Asia. It also offers a direct challenge to the United States.

U.S. defense secretary Chuck Hagel issued a statement of U.S. “concern” immediately after China’s ADIZ announcement. Hagel stated that “we view this development as a destabilizing attempt to alter the status quo in the region. This unilateral action increases the risk of misunderstanding and miscalculations.” In addition to noting that Washington would closely coordinate with its allies in the region, Hagel stated the Chinese announcement “will not in any way change how the United States military operates in the region.

A day later, Chinese Ministry of National Defense spokesman Yang Yujun rebutted the U.S. protest, and cautioned the United States “not to take sides” in the dispute between China and Japan. “We demand the U.S. side to earnestly respect China’s national security, stop making irresponsible remarks for China’s setup in the East China Sea Air Defense Identification Zone, and make concrete efforts for the peace and stability in the Asia Pacific region."

Keeping militaries apart and alert to the consequences of miscalculation is the biggest challenge for U.S., Japanese, and Chinese policymakers. This new ADIZ announcement only enhances risk and deepens suspicions. Cooperation in creating viable risk reduction measures ought to be the highest priority.

The militaries must have a framework for political oversight that prioritizes risk reduction rather than increased military involvement in shared maritime and airspace in the East China Sea. Japan’s military has long been inculcated with the norm of civilian control, and has an “exclusively defensive” doctrine that shapes training and operations. ASDF rules of engagement were publicly reconfirmed in December after the Y-16 incursion, the fist time this was necessary since a Soviet Backfire bomber violated Japanese airspace near Okinawa in 1987. Japan’s military has had the greatest interaction with Russian (former Soviet) air forces in the north, and has a regular consultative process to monitor military interactions and prevent risky behaviors.

Maritime risk reduction measures are also badly needed. The nascent High Level Maritime Talks that began in 2011 were halted after tensions erupted again in 2012. Ultimately, Japan and China will need an Incidents at Sea type agreement that outlines how commanders are expected to respond in cases of accidents or mistakes on the high seas. Even at the worst moments of the Cold War, U.S. and Soviet navies relied on each other for assistance in the case of accidents.

Popular sentiment in Japan and China has become highly sensitive to the island dispute, and both governments are hard pressed to find a way of managing their differences. This latest announcement by Beijing only exacerbates the risks that the growing interactions of Chinese and Japanese forces in and around the Senkaku Islands will lead to conflict. Even China’s Ministry of Defense acknowledged the dangers of last January’s fire control incident even as it denied that Chinese forces were responsible. Thus, at this moment where Beijing is refusing to discuss risk reduction with Tokyo, increasing the likelihood of further interaction between the militaries seems inexplicably reckless.