pacific forum History of Pacific Forum

Maritime Security in the East China Sea: Japan’s Perspective

Issues & Insights Vol. 21, SR 2, pp. 16-20

Volume Overview

“Maritime Security in the East China Sea: Japan’s Perspective” is the third chapter of Issues & Insights Vol. 21, SR 2 — Advancing a Rules-Based Maritime Order in the Indo-Pacific. Authors of this volume participated in the Indo-Pacific Maritime Security Expert Working Group’s 2021 workshop that took place, virtually on March 23-24. The working group, composed of esteemed international security scholars and maritime experts from Japan, the United States, and other Indo-Pacific states, was formed to promote effective U.S.-Japan cooperation on maritime security issues in the region through rigorous research on various legal interpretations, national policies, and cooperative frameworks to understand what is driving regional maritime tensions and what can be done to reduce those tensions. The workshop’s goal is to help generate sound, pragmatic and actionable policy solutions for the United States, Japan, and the wider region, and to ensure that the rule of law and the spirit of cooperation prevail in maritime Indo- Pacific.

Chapter Excerpt


This paper focuses on “the rule of law,” as a long-standing principle to maintain and defend maritime security. It has been the main pillar of Japanese diplomacy and ocean policy for almost a decade. This paper highlights key issues in the East China Sea, but without excluding the South China Sea. The rule of law forms as the fundamental principle for a Free and Open Indo-Pacific. Accordingly, an examination of the rule of law is important for understanding and coping with the situation in the East China Sea and the South China Sea.

After the introduction, a nuanced background of the tense situations in the East China Sea is provided. This paper has touched upon the Korea-Japan relationship in the Sea of Japan, for the purpose of comparing it with the China-Japan relationship. The confirmation of the three principles of the rule of law will follow. The subsequent sections will provide some analyses on the situations in the East China Sea and the South China Sea by applying each of the three principles.

Tense Situations in the East China Sea

In the East China Sea, tense situations have persisted mainly due to two factors that are closely related to each other. First, there is an issue and a dispute regarding the territorial sovereignty of the Senkaku Islands. According to Japan’s official position, while there has been an issue between China and Japan regarding the sovereignty of the Senkaku Islands, there is no dispute. This is in contrast to Japan’s position on the territorial sovereignty of the Takeshima Islands, between Korea and Japan, where there has been a dispute.

Second, there are undelimited maritime areas in the East China Sea due to a lack of agreements on maritime delimitation. The issue of territorial sovereignty over the Senkaku Islands has made the desired delimitation agreements very difficult to reach between China and Japan. The difference in positions between the two countries with respect to the international legal rules on maritime delimitation, particularly those under the United Nations Convention on the Law of the Sea (UNCLOS) is not the sole hurdle to overcome for achieving maritime delimitations. In delimitating maritime areas, the legal status and effects of islands to the delimitation line is a critical issue. Thus, without determining the territorial sovereignty of the island concerned, final delimitation lines are very difficult to be drawn. In fact, there are no delimitation agreements between China and Japan, on both the continental shelf and the exclusive economic zones. In 2008, they reached a mutual understanding and produced a political document on joint development of the continental shelf. It sets joint development zones that cross over the median line between the two countries. However, they have realized no significant progress in the development of the natural resources on the continental shelf.

China, irrespective of the mutual understanding on joint development, has continuously constructed oil rigs that are very near to the median line between the two countries. These acts are highly proverbial as China has already gone beyond exploration and unilaterally engaged in the exploitation of the natural resources of the continental shelf. Furthermore, by taking advantage of the non-existence of any delimitation agreement on the exclusive economic zones, China has periodically conducted marine scientific research in the sea area located on Japan’s side of the median line between the two countries. Under UNCLOS, a foreign country wishing to conduct marine scientific research in the exclusive economic zone of a coastal state is required to seek consent from that coastal state.

In addition to the delimitation problems regarding continental shelf and exclusive economic zones between China and Japan, there has been a seriously tense situation in the territorial sea surrounding the Senkaku Islands. These tensions have grown more severe due to the enactment of the amended Coast Guard Law of China, on February 1, 2021. Both China and Japan are claiming territorial sovereignty over the Senkaku Islands and the territorial sea thereto. To demonstrate its territorial sovereignty, China persistently dispatches its public vessels, warships, and in some cases, fishing boats flying Chinese flags. Those public vessels chase fishing boats flying Japanese flags as if they were conducting law enforcement against the Japanese fishing boats. Accompanying the public vessels, China also dispatches its warships. Its aim is overt demonstration of China’s territorial sovereignty over the Senkaku Islands. Chinese fishermen, sometimes deploying in groups of several hundred fishing boats, include maritime militia vessels. Considering the tense situation, unilateral claims of rights over maritime areas and aggressive activities backed up by the presence of a military force seriously contribute to the escalation of the tense situation in the East China Sea.

Download the Full Volume

Atsuko Kanehara is Professor at Sophia University, President of the Japanese Society of International Law, Vice President of the Japan Society of Ocean Policy, Councilor for the National Headquarters for Ocean Policies of Japan for the Government of Japan, Advocate in the Southern Bluefin Tuna Cases, and Counsel in the Whaling in the Antarctic Case.

The Indo-Pacific Maritime Security Expert Working Group’s 2021 workshop and this volume were funded by a grant from the U.S. Embassy Tokyo, and implemented in collaboration with the Yokosuka Council on Asia Pacific Studies (YCAPS).

The statements made and views expressed are solely the responsibility of the authors and do not necessarily reflect the views of their respective organizations and affiliations. For questions, please email [email protected].

Photo: A Coast Guard patrol vessel passes by Uotsuri, the largest island in the Senkaku/Diaoyu chain. Now uninhabited, it used to be home to 248 Japanese, in a community of 99 houses in the late 1890s. Source: Al Jazeera English/Creative Commons