In November of last year, the RAND Corporation published a report titled In Line or Out of Order? China’s Approach to ADIZ in Theory and Practice, on the establishment of China’s East China Sea (ECS) Air Defense Identification Zone (ADIZ) and the potential of a South China Sea ADIZ. Though comprehensive, the report suffers from a few common misperceptions of China’s ADIZ shared by many Western scholars and policymakers. These misperceptions, which touch on the fundamental nature of China’s ECS ADIZ, have received insufficient attention in the media and if left unclarified, could worsen distrust between governments and escalate tensions in the region. While this article does not seek to provide a comprehensive analysis of China’s strategy and motivations in the ECS, the author hopes that establishing the basic legal facts regarding the ECS ADIZ can facilitate constructive dialogue between the relevant actors going forward.

I. Establishing an ADIZ that includes “contested territory” does not legitimize a sovereign claim, and is legally acceptable.

First, the report reiterates the conventional argument that “China’s primary purpose in declaring an ADIZ was to advance and strengthen its claim to the islands, most likely as a reaction to the Japanese government’s purchase of three of the five islands from private Japanese citizens in late 2012.” The purpose attributed to China is logically inconsistent, though, with the report’s earlier assertion that an ADIZ “does not grant the declaring state sovereignty over that airspace.” From a purely international-law-based perspective, an ADIZ itself has no implication of sovereignty claim at all. The establishment of an ADIZ, whether including or excluding contested territory, is irrelevant to the claim. As an example, Japan’s ADIZ does not cover the disputed Takeshima (Dokdo) Island, nor does it cover the Northern Territories (Southern Kurils), which does not mean Japan cedes its claims; similarly, South Korea’s ADIZ covers Takeshima, which Tokyo would agree legally bears no relevance toward its claim. Taiwan authorities’ ADIZ does not cover the Diaoyu (Senkaku) Islands, which certainly bears no relevance on their sovereignty claim either. This understood, it would be silly for China to declare an ECS ADIZ with the primary intent of advancing and strengthening its claim to the islands.

Second, existing precedents demonstrate that an ADIZ covering contested territory does not make it legally unacceptable. Setting aside the fact that Japan’s ADIZ covers the same disputed Diaoyu Islands, there are several international precedents for governments establishing an ADIZ over indisputable territory of another country. For example, the South Korean ADIZ—originally established by the United States in 1951, later extended south in 2013—covers a large portion of North Korea. Another case is the Taiwan authorities’ ADIZ, which covers part of Japan’s Yonaguni Island. In response, Japan in 2010 unilaterally declared an extended ADIZ line that covered Yonaguni Island completely. Japanese officials with the Ministry of Foreign Affairs told the Taipei Times that “ADIZ demarcation is at the discretion of each country, [so] it was natural for Japan not to seek prior approval” from the Taiwan authorities. Taipei denies the validity of that change, and to this day insists on the 123°00′ E line established by the United States as the limit of the Japanese ADIZ decades ago. If including the indisputable territory of another country in an ADIZ is not contrary to international practice, China’s enclosure of contested territory should not be criticized either.

Accordingly, China’s establishment of the ECS ADIZ should perhaps be viewed less as primarily a move to strengthen its claim over a contested territory, and more to do with China’s concerns over protecting its national security interests in the ECS, where Japan’s ADIZ covers a large area and China formerly had none.

II. China’s ADIZ rules may only theoretically apply to the islands.

The RAND report argues that both Japan’s ADIZ and China’s ADIZ include the Diaoyu Islands. This is not precisely correct. The November 2013 Chinese government statement announcing the ECS ADIZ made it clear that “the zone includes the airspace within the area enclosed by China’s outer limit of the territorial sea [emphasis author’s own] and the following six points: 33°11’N (North Latitude) and 121°47’E (East Longitude), 33°11’N and 125°00’E, 31°00’N and 128°20’E, 25°38’N and 125°00’E, 24°45’N and 123°00’E, 26°44’N and 120°58’E.” Because China maintains the islands are “an inseparable part of the Chinese territory” and thus generate a territorial sea, China’s ADIZ borders the outer limit of the territorial airspace of the islands and therefore surrounds the national airspace of the islands, but does not include it.

Setting the above aside, however, China technically would have the legal right to extend the application of ADIZ rules to the islands. According to U.S. practice—specifically, title 14, part 99 of the Code of Federal Regulations—ADIZ rules can apply not only to the declared ADIZ area, but also any “defense area” which the declaring state may define and designate by domestic law. The U.S. defines a defense area as “any airspace of the contiguous United States that is not an ADIZ in which the control of aircraft is required for reasons of national security.” China of course has the same right to define its own defense area, and to designate the Diaoyu Islands as such an area if it so chooses.

III. No hope of governing the dispute of overlapping ADIZs?

The RAND report does not address a significant and related problem which, if resolved, could provide a basis for improving relations and coordination in the region. China’s ADIZ overlaps significantly with the pre-existing ADIZ and Flight Information Region (FIR) of Japan, a state of affairs over which the Japanese side raised serious complaints. Though it does not govern ADIZs, the Convention on International Civil Aviation (also called the Chicago Convention) does provide rules for FIRs. On March 10, 2014, the delegations of Japan and the United States submitted a letter to the International Civil Aviation Organization (ICAO) Secretariat regarding “the issue of freedom of overflight by civil aircraft in international airspace” and management of civil air traffic in FIRs. Specifically, the delegations sought to determine “whether a country has the right to give orders to, or restrict the flights of, commercial aircraft in airspace outside the jurisdiction of its civilian air traffic controllers,” a question which can be assumed to pertain to China’s ECS ADIZ rules. According to the dispute settlement procedure provided in Articles 84 and 85 of the Chicago Convention, Japan may opt to file a formal complaint before the ICAO. This option may not align with its national interests, however, because Japan’s ADIZ also extends outside its FIR and into other countries’ FIRs, such as the Taipei FIR and Incheon FIR. If Japan accuses China of using its ECS ADIZ to restrict the operation of civil aircraft outside of Chinese FIRs, it must reckon with the fact that Tokyo does the same.

Because a legal framework governing the establishment or enforcement of ADIZs does not exist, overlapping ADIZ disputes can only be resolved through diplomatic consultations between relevant parties. To this end, the recent negotiations between China and Japan on establishing the China-Japan maritime and air liaison mechanism are well poised to reduce tensions, if they come to fruition. Thus far, the two sides have reached a principled agreement, and as of January are looking to sign it at an early date.

About Cao Qun

Dr. Cao Qun joined the China Institute of International Studies (CIIS) in 2012. He is currently an associate research fellow with the Center for Maritime Security and Cooperation at CIIS, and an associate senior editor of China International Studies. His research specializes in South China Sea issues, the Sino-Japanese dispute over the Diaoyu/Senkaku Islands, and air defense identification zone regulations. The views expressed in this article are those of Dr. Cao Qun alone. They in no way represent the position of the China Institute of International Studies or any other organizations.