Air Defence Identification Zone
The Air Defense Identification Zone is airspace over land or water in which the ready identification, location, and control of civil aircraft over land or water is required in the interest of national security. China's Defence Ministry announced its ADIZ over a vast area in the East China Sea on November 23, 2013, which covers the area around the Diaoyu islands, controlled by Japan and known as the Senkaku Islands. The establishment of this zone drew strong opposition from Japan, the US and South Korea, becoming a flashpoint in East Asian politics and security.
US Vice-President Joe Biden's balancing act over China's air zone
Visiting vice-president seeking to back key ally Japan while reassuring China of US intentions
US Vice-President Joe Biden will seek a delicate balance between calming military tensions with China and backing ally Japan against Beijing on a trip to Asia that is being overshadowed by a territorial row in the East China Sea.
Japan reiterated on Monday that Tokyo and Washington had both rejected Beijing's move to set up an air defence identification zone that includes islands at the heart of a bitter Sino-Japanese feud - despite the fact that three US airlines, acting on government advice, are notifying China of plans to transit the zone.
"The US government has made it clear that it is deeply concerned about China's establishment of the air defence identification zone, and that it will not accept China's demands regarding operations in the zone," Japanese Chief Cabinet Secretary Yoshihide Suga said.
Chinese Foreign Ministry spokesman Hong Lei said China appreciated the US urging its airlines to notify China of flight plans, but chastised Japan for "deliberately politicising" the issue.
In Tokyo today, Biden will likely assure Japan that the military alliance with the US remains valid as the government of Prime Minister Shinzo Abe wrangles with China over the islands. Yet, he will also try to calm tensions with key trade partner China over the same territorial dispute when he goes to Beijing.
"It's especially important ... that we continue to amplify our messages that we are and always will be there for our allies, and that there is a way for two major powers in the US and China to build a different kind of relationship for the 21st century," a senior Obama administration official said.
Washington takes no position on the sovereignty of the islands, known as the Diaoyus in China and the Senkakus in Japan. However, it recognises Tokyo's administrative control and says the US-Japan security pact applies to them, a stance that could drag the US into a military conflict it would prefer to avoid.
Some experts said China may have overreached with the zone, and Biden is expected to suggest ways out of the crisis when he meets President Xi Jinping in Beijing tomorrow.
"What the Americans can hope to do is to try to tell the Chinese that this ratcheting up is not very clever and is counterproductive and that there is a way out, which is for the Chinese simply to de-emphasize [the zone] and not to enforce it," said Jonathan Eyal, international security studies director at London's Royal United Services Institute.
Few foresee a quick resolution to the dispute. "China will probably say to Biden that this is a standard practice for more than 20 countries. Why the fuss?" said Jia Qingguo, associate dean of the School of International Studies at Peking University.
"It is helpful for the two sides to gauge each other's intentions and clarify issues and develop some kind of understanding as to what to expect. But this issue will probably linger on."