Russia and the Asia-Pacific Region

Tetsuya Toyoda: Why Can the Chinese ADIZ be a Threat to the Peace in East Asia

December 26, 2013

An Air Defense Identification Zone (ADIZ) is airspace which extends beyond national borders. It has no basis in international law, but is not illegal as long as it does not violate existing rules of international law. Its purpose is usually to identify aircrafts approaching the territorial airspace. Even though it is only in the territorial airspace the state is allowed to take measures of enforcement, by setting up an ADIZ, thanks to an early identification, the state can better prepare for its measures in the territorial airspace. But the use of physical forces against foreign aircrafts (even for allegedly security reasons) out of the territorial airspace is against international law, whether or not it is in the ADIZ.


Let’s be clear about this. Even if a state has one, it does not increase the rights it has against foreign aircrafts approaching its soil. Not all countries have an ADIZ, because it is not really meaningful. That is likely the reason why only dozens of countries have ADIZs, while virtually all countries have their Flight Information Regions (FIRs) to regulate air traffic. FIRs are necessary, while ADIZs are unnecessary.


Chinese Concept of ADIZ


The Chinese concept of ADIZ roughly follows what is generally understood as such by other countries. But there may be confusion with the territorial airspace. After the November 23 announcement, a military legal expert wrote in China's semi-official newspaper China Daily (Renmin Ribao)1):


An air defense identification zone, as an area of airspace established by a coastal state beyond its territorial airspace, is designated to identify and monitor aircraft that enter the zone. Such zones, simply put, are part of a country's security early warning system, which was initiated by the US and Canada in the 1950s amid the East-West military confrontation. Air defense identification zones now surround much of North America, and more than 20 countries and regions, including Japan, South Korea and the Philippines, have established such zones. Rules for the zones vary from country to country, but all have the same defensive nature.


Yes, that is correct. He has nicely pointed out the fact that it was the Americans who started such an unfriendly practice as setting ADIZs. Then, the Chinese expert continues:


Although countries retain the right to identify and monitor foreign aircraft entering their air defense identification zones, they do not deny aircraft entry, they will only intercept and eject aircraft that violate their rules or pose a security threat.


Wait a second. It is very right to say that a state cannot deny aircraft entry because of the ADIZ regulations which are just domestic rules. But what if "they will only intercept and eject aircraft that violate their rules or pose a security threat"? It is clearly a violation of international law if a state ejects an aircraft on the grounds of domestic rules. You can do so in the territorial airspace but in not the part of ADIZ which is not in the territorial airspace. The assimilation of the ADIZ to the territorial airspace can fundamentally change rules of international law regarding airspace.


Possible Violation of the UN Charter


The Chinese ADIZ is problematic all the more because it was set over the islands which they do not control to date.


Think of the Southern Kurile Islands. Japan has been persistent in claiming its sovereignty to what they call 'Northern Territories,' embarrassing, I know, the Russian government and many of my Russian friends. But Tokyo never included those islands in the Japanese ADIZ. In the same token, Tokyo never included the Takeshima (which is under the South Korean control as Dokdo) in the Japanese ADIZ. Setting an ADIZ and declaring the exercise of enforcement power over the Etorofu Island, for example, would be tantamount to declaring that the Japanese fighters would threaten Russian aircrafts flying over the island which the Russians consider theirs. This would certainly be in violation of international law even if the island is legally Japanese (according to the Japanese), because of the relevant UN Charter provisions, among which Article 2(3) provides: "All Members shall settle their international disputes by peaceful means in such a manner that international peace and security, and justice, are not endangered." Japan can continue to make legal claims against Russia as much as it likes (which by the way does not create any legal obligation on the Russian side to accept such claims), but Japan must not use physical forces to threaten the Russians, saying "This is our territory!"


This is what China can be doing in the near future. For the moment, the Chinese government is not clear yet whether it would use physical forces to 'protect' its ADIZ, but once it clarifies its intention to do so, it becomes a flagrant violation of international law. As long as the ADIZ has no chance to be operated in that way, it poses no problem of international law. There is a precedent. Taiwan used to have its ADIZ covering part of Japanese island of Yonakuni (even though Taiwan has no legal claim to the Yonakuni Island). This did not raise any serious problem because the Japanese side was sure that the Taiwanese forces would never use physical forces in the Japanese airspace even if it was part of the Taiwanese ADIZ. Such is not the case with People's Republic of China and the Japanese side cannot avoid being worried about the possibility of Chinese exercise of enforcement power in the area which is actually under Japanese control .


Tactically Brilliant, Strategically Catastrophic


As mentioned above, the ADIZ is just an area of surveillance without any physical enforcement. But people around the world have common misunderstanding to think of it as territorial airspace. When Beijing declared on 23 November 2013 its ADIZ in the East China Sea, people around the world thought it was against international law. It wasn't. For Chinese leaders, it must have been so amusing to see American and Japanese politicians frustrated to death by this "provocative, dangerous, but perfectly legal"2) move.


However, strategically speaking, Beijing might have made a serious mistake. Its mistake is not in international politics, but in domestic politics. People in China, as elsewhere, do not see much difference between the ADIZ and territorial airspace. Once the area of Chinese airspace is clarified to their eyes, the Chinese public would not tolerate the government not reacting to Japanese and American military aircrafts flying there unpunished.


Conclusion: Whither the PLA?


ADIZs in general are consistent with international law. But China seems to have a particular understanding of ADIZ which is not consistent with international law. In addition, by setting the ADIZ over the islands under foreign control, it has declared its readiness to 'retrieve' the lost territory through threat and/or use of force. The illegality of the Chinese ADIZ is latent and can be avoided by appropriate rules of operation. However, now Beijing is driven by the hawkish of the People's Liberation Army and enthusiastic nationalism, the risk of illegal military operation for the sake of ADIZ may be unavoidable in the near future. Where are they heading for?



1) China Daily, "China's ADIZ is justified (2)", 13:11, 2 December 2013, accessed on 20 Dec. 2013 at

2) Julian Ku, "Meanwhile, China Draws a Provocative, Dangerous, But Perfectly Legal Air Defense Identification Zone in the East China Sea", Opinio Juris, 24 November 2013, accessed on 20 Dec. 2013 at



Tetsuya Toyoda, associate professor of Akita International University (Japan), fellow at the Woodrow Wilson Center for Scholars (U.S.),  and visiting professor at the Far Eastern Federal University (Russia)


From the editors:

The editors of this blog invite experts to share their views on the controversial issue of air defense identification zones in the East China Sea. We are ready to publish them here. You can contact the editors at or

Share this article

Poll conducted

  1. In your opinion, what are the US long-term goals for Russia?
    U.S. wants to establish partnership relations with Russia on condition that it meets the U.S. requirements  
     33 (31%)
    U.S. wants to deter Russia’s military and political activity  
     30 (28%)
    U.S. wants to dissolve Russia  
     24 (22%)
    U.S. wants to establish alliance relations with Russia under the US conditions to rival China  
     21 (19%)
For business
For researchers
For students