Geostrategic Importance and Natural Reserves of East China Sea

Authors: Nabel Akram, Komal Tariq*

The ECS is one of the largest marginal seas in the world. Its surface area covers this region receives a tremendous inflow of freshwater and terrestrial sediments mainly from mainland China. The ECS is connected with the SCS the Yellow Sea the Sea of Japan and the Pacific Ocean (Niu, 2016). The importance of the ECS China lies in its proximity to strategically important shipping lanes, and in their significant fishing grounds and oil deposits  (O’Rourke, 2015). Economically, the ECS is at the crossroads of global commerce and an increasingly vital source of both food and energy resources. Politically, cooperation in this sea is a growing test of rising Asia’s peace and prosperity, as well as a test of China’s narrative of its peaceful rise.


The East China Sea is bounded on the East by Kyusu and the Ryukyu, on the South by Taiwan, and on the West by mainland China. It is connected with the South China Sea by the Taiwan Strait and with the Sea of Japan by the Korea Strait; it opens in the North to the Yellow Sea (Kim S. K., 2012).  Territories with borders on the sea (clockwise from north) include: South KoreaJapanTaiwan, and Mainland China. East China Sea: 770,000 square kilometers with an average depth of 370m.

 Economic importance

The ECS is a very productive region. China, Japan, and North and South Korea actively fish in the area. Most of the fishing is done by small local boats, with some larger trawlers being used to catch: Tuna, mackerel, shrimps, sardines, milkfish, sea breams, croakers. Shellfish and seaweeds are also harvested. Petroleum and natural gas deposits have been discovered under the sea’s continental shelf  (Niu Y. , 2016). As the world becomes more energy dependent, such discoveries have led to disputes between the bordering countries over control of areas with potentially exploitable hydrocarbon reserves. Particular focus is on the regions around deep trenches, straits, rocks, and uninhabited islands. A small amount of China’s oil and natural gas production comes from offshore wells in the ECS (Wei, 2014).

Strategic importance

Strategically, the ECS are the place where Chinese military modernization is most likely to directly challenge US’s long, postwar dominance. In other words, the ECS are central to Asia-Pacific security. The stakes are high and increasing in this sea, and both China and Japan must place a premium on avoiding war, managing disputes, slowly building institutions and advancing joint cooperation (Yee A. , 2017).

 Natural Recourses

The East China Sea is rich in oil and gas resources and has long been the target of both China and Japan and other neighboring countries facing China’s maritime areas. The East China Sea may have abundant hydrocarbon resources, especially natural gas, although the region is underexplored. China and Japan, the two largest energy consumers in Asia, are both interested in using natural gas from the East China Sea to meet rising domestic demand. However, unresolved territorial disputes make exploration and development of these resources difficult.

Hydrocarbon reserves  

Hydrocarbon reserves in the ECS are difficult to estimate, but EIA estimates the East China Sea contains 60-100 million barrels of oil in proven and probable reserves, and 1-2 trillion cubic feet (Tcf) of proven and probable natural gas reserves. Estimates of undiscovered resources, which do not take into account economic and technological factors relevant to bringing them into production, show significant resource potential. Chinese sources estimate as much as 70-160 billion barrels of oil and 250 Tcf of natural gas in undiscovered, technically recoverable resources.

Chinese authorities seek to increase offshore natural gas production to supply Shanghai and nearby cities. However, the ECS is not expected to become a significant supplier of oil for a number of years, even after resolution of the territorial disputes.

Source: Asia Maritime Transpierce intuitive 2016

 Natural Gas Exploration East China Sea


The U.S. Energy Information Administration (EIA) estimates the ECS contains nearly 200 million barrels of oil in proven and probable reserves and 1-2 trillion cubic feet of proved and probable natural gas reserves. If estimates of these oil reserves are true and they can be extracted, China would no longer have to import them from the Persian Gulf region or SCS consequently diminishing the chances of its energy supply lines to potential disruption. Tides in this region during December 2015 ranged from -0.1 feet to 6.6 feet indicating an area affected by monsoonal winds, typhoons, strong storms, and local winds, and a growing population which can significantly influence regional aviation, meteorological, and shipping activity (Chapman, 2016, p. 16).

Graph of Petroleum Resources in ECS

Oil importance for China and Japan

China is the world’s largest energy consumer and the second largest importer of oil after the United States. Because of its growing reliance on natural gas in recent years, China is now a net importer of natural gas. EIA forecasts continued growth in Chinese oil and natural gas consumption, necessitating new supplies to meet demand.

Japan is the world’s third largest net importer of crude oil, and the world’s largest importer of liquefied natural gas. Japan is expected to continue to rely heavily on imports to meet future consumption needs.


Figure-5 Graph of Natural Gas Resources in ECS

The Chunxiao gas field is a natural gas field below the ECS within the Chinese EEZ, about 4 km to the west of the EEZ border claimed by Japan which is disputed by China. The Chunxiao gas field is the first of a group of four natural gas fields in the Xihu Trough being developed by China: the other ones are Tianwaitian, Duanqiao, and Canxue.

Chunxiao gas field in the East China Sea

Senkaku Island in the ECS

The disputed Senkaku/Diaoyu Islands are located some 120 miles north-east of Taiwan, approximately 250 miles west of Okinawa, and approximately 100 miles north of the most western Ryukyu Islands. The Senkaku Islands (circa 7 square kilometers) consist of five uninhabited islets and three barren rocks  (Chaudhury, 2016). They are situated at the edge of the ECS`s continental shelf fronting the Okinawa Trough to the south. The depth of the surrounding waters is about 100-150 meters, with the exception of a deep trough in the continental shelf They are situated at the edge of the ECS`s continental shelf fronting the Okinawa Trough to the south. The depth of the surrounding waters is about 100-150 meters, with the exception of a deep trough in the continental shelf just south and east of the islands, that separates them from the Ryukyu Islands.  just south and east of the islands, that separates them from the Ryukyu Islands  (Drifte, 2008). It is worth noting that China’s claim to the Senkaku/Diaoyu Islands is basically an extension of its claim to Taiwan. This study is not concerned with the rival Taiwanese claims but focuses instead on the dispute between China and Japan.

 Arguments from China and Japan on Senkaku Island 

Historical Background

Historically, the Senkaku/Diaoyu Islands have been well-known and documented. There is a large amount of evidence particularly in Ming Dynasty (1368-1644) records that references the islands, their history, and their usage (Hui, 2010). The first description of the islands first appeared in 1534 when a Chinese envoy visited Ryukyu (an independent kingdom south of Japan at the time). The islands were very well-known by the Ryukuans and the Chinese, but they functioned almost exclusively as a marker for ocean navigation primarily due to their peculiar form, isolation from strong currents, and size (Shigeyoshi, 2010). China uses historical documents from the Ming Dynasty to justify their claims to the Diaoyu/Senkaku Islands. However, these documents do little to show historical Chinese ownership.

Importance of Senkaku Island

The Senkaku Islands have great economic and strategic advantages. The islands are near important shipping lanes where large amounts of international trade transit. There are also fishing areas both sides view as important, as well as possible natural resources like oil, gas, and mineral deposits around the islands. The dispute about the overlapping of the demarcation of the exclusive economic zone (EEZ) by the United Nations Convention on the Law of the Sea (UNCLOS) is also an important factor that makes the Senkaku Islands so sought after (Park, 2015, p. 5).

Their location is also strategically important due to the rising competition between China, Japan, and the United States for military supremacy in the Asia-Pacific region. According to a scholar at the Chinese academy of social sciences, if Japan manages to force China to abandon its claims on the islands, the American – led Asia-Pacific order underpinned by the US-Japan alliance would undoubtedly be reaffirmed. On the other hand, if China successfully fulfils its sovereign claims over the islands, then the era of the United States dominating the Asia-Pacific maritime order will end on the spot (Chaudhury, 2016).

Economics Value

Scholars have pointed to the economic value of the Senkaku/Diaoyu islands which drives the China-Japan rivalry over the islands. Nevertheless, while the islands themselves do not contain any valuable natural resources, the surrounding waters are tipped to contain rich hydrocarbon resources, such as oil and gas. The 1968 United Nations survey argued that the hydrocarbon resources in the ECS are comparable to those of Saudi Arabia. Given the China’s growing dependence on energy imports and the new urgency that the debate over energy security gained in China, China’s grasp of the valuable economic resources would be undoubtedly strengthened by occupying the Diaoyu/Senkaku islands. Drifte quoted both Chinese and Japanese estimates of the amounts of hydrocarbon resources, which confirm the rich hydrocarbon resources located in the adjacent waters to the islands (Drifte, 2008).

Strategic Value

Their location is also strategically important due to the rising competition between China, Japan, and the US for military supremacy in the Asia-Pacific region. Strategic value of the disputed Senkaku/Diaoyu islands has been cited as a potential cause of conflict in the dispute (Wiegnad, 2015). While it is true that the islands occupy a central location between Mainland China, Taiwan, and the Ryukyu Islands, these are tiny, rugged islands in notoriously difficult seas. They could host a small helicopter base and a radar station at best. Further, the very centrality of their location reduces, rather than increases, their strategic value. Unlike the Ryukyus, which act as a geographical border between the Pacific and the ECS, the disputed islands are surrounded by the ECS itself; therefore, control of the islands does not affect access to Pacific (O’Shea, 2015). Although the islands are of limited strategic significance, the surrounding ECS itself is vital to both states, not least due to their dependence on energy imports, much of which come from the Middle East via the Straits of Malacca and the South China Sea (SCS). Major ECS trade routes continue north through the Tsushima Straits into the Sea of Japan, as well as out through the Osumi and Miyako Straits into the Pacific Ocean. Both Japan and China rely on these sea lines of communication (SLOCs) not only for energy but also for food imports; both economies are also highly dependent on exports to the United States and other overseas markets. The strategic significance of the ECS, then, should not be underestimated. China’s maritime security strategy has been based on developing the capacity to secure the maritime space up to the ‘‘first island chain,’’ including the ECS and SCS (Yee, 2017). Moreover, the strategic significance of the ECS SLOCs may actually militate against conflict. Any armed conflict over either the islands or the surrounding seas would be disastrous for regional shipping, leading to grave consequences for all the region’s economies. The importance of continued economic growth and prosperity as a key of legitimacy for continued Chinese Communist Party (CCP) rule means that China is unlikely to undermine shipping in the ECS, its ‘‘main gateway to economic growth (Patalano, 2012).

 Trade Routes

The East China Sea (ECS) is gaining an increasingly central role in Sino-Japanese relations as it is crucial to the economic development and political affirmation of both countries, for whom the main sea routes crossing the ECS offer vital arteries for trade and energy imports  (Patalano, 2014). Maritime shipping routes are crucial for all East Asian nations. The ECS and SCS are primary trade routes for the littoral states and carry a significant share of world merchandise trade. In Northeast Asia, key regional trade shipping lanes are located in the ECS. Though relatively dependent on maritime trade, China does not border any oceans, only seas. Due to its geographic position, China’s maritime trade is highly reliant on the shipping lanes in the East China Sea that connect vessels to the rest of the world. Arguably for the first time in China’s history, continued economic growth is dependent on maritime access and security (Dossani, 2016).

*Komal Tariq, Master in International Relations and Senior Teacher of Social Studies in Educators.

Nabel Akram
Nabel Akram
Master of Science in Political Science Former Teacher Assistant UMT Lahore