Senkaku Islands: How Strong Are China's Claims?

China's provocative attempts at territorial grabs in the East China Sea were fully displayed yet again. On March 31, it was reported that two Chinese Haijing Coast Guard ships enteresd Japanese waters around the Senkaku Islands, Ishigaki City, Okinawa Prefecture. They stayed for more than two days before leaving the waters. 

More alarmingly, it was the seventh time in 2024 for a Chinese government ship to enter Japanese waters around the islands. The two vessels tried to approach Japanese fishing boats around the Senkaku chain. This is according to the Japan Coast Guard's 11th regional headquarters in Naha.

China is upping the ante by challenging the sovereignty of the Senkaku Islands with each passing year. In the process, it is not just questioning sovereignty, but the concepts and consequences of statehood at large. 

The Senkaku Islands are one of the many conflicts regarding statehood, territory, and titles that China seeks to keep afloat. Its aim is to retain the bargaining edge with Japan over the strategically located island group.

Understanding Territorial Concepts

As concepts, "original title" and terra nullius often operate in combination. They have functioned as bases of the traditional law of territory. Terra nullius is a Latin term meaning "land belonging to no one/no-man's land." 

Before examining the concept of original title, it is necessary to define "title." The concept of title is used in public international law to demonstrate that a territory belongs to a state. Title to territory is usually defined as "a vestitive fact of territorial sovereignty" or "a source of territorial sovereignty." This is cited in a paper titled "Title to Territory in the Post-Colonial Era" published in the European Journal of International Law, 2015 edition. 

In other words, when a state has title to a certain territory, that state's control over the territory in question is legally justified. Other states must respect that state's control over said territory. 

Modes of Territorial Acquisition

More importantly, customary law states that, historically, five modes of territorial acquisition have emerged. They are mechanisms by which countries legally acquire territory: discovery and occupation, conquest, prescription, cession, and accretion.

The first element, discovery, largely depends on the absence of prior claims on the territory. Accordingly, the territory must be terra nullius. The second element, effective occupation, consists of two additional sub-elements. First, the nation must exhibit the intention to act as a sovereign. Second, the nation must also exercise actual sovereign authority. 

Though the Senkaku Islands are volcanic rock formations, accretion is a theory that is unlikely to bolster either China's or Japan's claims for sovereignty. All volcanic growth of the Senkaku Islands probably occurred before any claim to the islands was made.

Why Japan's Claim is Stronger

Occupation and discovery are the most likely avenues for both countries to claim sovereignty. And in terms of both discovery and occupation, the strongest argument stands in favor of Japan. This also holds considering Japan incorporated the islands as vacant territory. Additionally, Japan's effective control over the islands went unchallenged for a very long time. 

Further bolstering the Japanese claim under discovery and occupation is that Tokyo discovered the islands when they were still terra nullius. Meanwhile, there is no evidence that China ever established settlements or occupied the islands as a colony.

While deliberating the contesting claims over the Senkaku Islands, rules of contemporary international law bear immense significance. The rule establishing the terra nullius positional concept is especially important.

Japan conducted official surveys of the Senkaku Islands in 1883 and 1887. Subsequently, it made a Cabinet Decision on January 14, 1895 to erect a marker on the islands and incorporate them formally into Japan. Through all of this, China did not put up any official/public protest on any of these actions on record. It did not officially contest Japan's exercise of authority and occupational control over the Islands.

Another key point of divergence that applies to the islands is the backdrop of "administration" as distinguished from "sovereignty." China argues it established sovereignty through the classical mode of "discovery" of the islands. However, Japan, which has administered the islands since the 19th century, comes closer to fulfilling all requisite legal requirements to hold title over the Senkaku Islands under contemporary international rules and law. That said, China will continue to exert maximum political and military pressure to escalate the conflict in the East China Sea.

RELATED:

• Senkaku Islands Survey: Tensions in the Surrounding Waters
• Japan's Three Territorial Problems Viewed Under the Glare of International Law
• Lawfare by China against Taiwan Aims to Create New Norm: Japan Is Next
• EDITORIAL | At Senkaku Islands, Fight China for the Intruder that It Is

Author: Dr Monika Chansoria

Learn more about Dr Chansoria and follow her column "All Politics is Global" on JAPAN Forward, and on X (formerly Twitter). The views expressed here are those of the author and do not reflect the views of any organization with which she is affiliated.