Debates Concerning the Incorporation of Peripheral Islands into the Territory of Japan

Debates Concerning the Incorporation of Peripheral Islands
into the Territory of Japan*
Takai Susumu**
Abstract
Japan introduced international law when Japan ended the seclusion policy of the Edo
period and started to interact with Western countries. Japan took measures to possessand establish title to peripheral islands on the basis of international law. The process bywhich peripheral islands in the Pacific, the Sea of Japan, the East China Sea, and the Sea of
Okhotsk were incorporated into Japanese territory will be examined, and the objections ofneighboring countries to some of these acquisitions will be discussed.

IntroductionDelimitation of the scope of a state ʼ s territor y, as well as the acquisition and lossof territories are fundamentally made on the basis of international law. Since thecountr y ʼ s opening to the global community in the mid-19th centur y, Japan has
respected the principles of international law. Measures to incorporate islands near
Japan into the countryʼs territory were progressively implemented, based on the law of nations.
However, disagreements over Japanʼs sovereignty over Takeshima, the Senkaku Islands, and theNorthern Territories have been voiced by neighboring countries since the signing of the San
Francisco Peace Treaty after World War II.
There are four types of territorial acquisition, according to the traditional precepts ofinternational law. The first two are accretion and occupation, where territories are seized bya unilateral act of a state. In accretion, a state unilaterally acts to acquire territor y by taking
advantage of natural phenomena. A well-known example of accretion is New Nishinoshima Island,
which is an island that became Japanese by appearing next to Old Nishinoshima Island in the
countryʼs territorial waters, through the natural phenomenon of an underwater volcanic eruption.
In the case of islands on the high seas created by underwater eruptions, the new island becomes
an unoccupied territory that belongs to no state, and can be possessed by the first state to lay
claim to it.
The other type of acquisition involving unilateral acts of a state is known as occupation.
Strictly speaking, there is a separate type of occupation known as prescription, but I will only
explain occupation as it relates to Japanese island territories. Occupation is a unilateral act of astate whereby land categorized as terra nullius―meaning “nobodyʼs land”―is incorporated into
the stateʼs territory. To be recognized under international law, the occupation must be of land thatis recognized as belonging to nobody. It does not matter if the land is already inhabited. Simply
discovering the territory is not recognized as an act of occupation, and effective control must be
This article is based on a presentation made by the author at the symposium “Territory and Maritime
Issues in East Asia and their Origins” held by JIIA, Doshisha University Center for Study of South China
Sea and Faculty of Law Doshisha University on March 2, 2019.
** Takai Susumu is a Special Research Fellow at the Sasakawa Peace Foundation.

*

20
Japan Review Vol.3 No.2 Fall 2019

Takai Susumu

exercised over the territory so as to make clear the stateʼs intention to take possession of it.
There are also two types of territorial acquisition that are based on a mutual agreement
between states: incorporation and cession. Incorporation signifies the transfer of a territory in its
entirety to a foreign state on the basis of a mutually agreed treaty. A famous example is the JapanKorea Treaty of 1910, by which the state on the Korean peninsula was recognized as Japanese
territory through a treaty that was agreed upon by the Korean and Japanese governments.
Cession is an act of territorial acquisition recognized in international law whereby part of aterritory is transferred to another state, again by a mutual pact. This can be further divided into
peacetime and wartime cession. Peacetime cession refers to the expansion of a state throughthe purchase or exchange of territory. In Japanʼs case, we have the 1875 Treaty of St. Petersburg
by which Japan exchanged Karafuto (Sakhalin) Island for the Russian territory of the ChishimaIslands (Kuril Islands).
Wartime cession refers to a mutual agreement on the transfer of territory in a peace treaty
that ends a war. To legally terminate hostilities, a peace treaty that incorporates stipulations on
territory must be signed. An example of this is the 1895 Treaty of Shimonoseki. As a result of theFirst Sino-Japanese War, the Qing territory of Taiwan was ceded to Japan and made a Japanese
territory. The 1905 Treaty of Portsmouth was signed after the Russo-Japanese War, by whichsouthern Sakhalin Island was transferred to Japan from Russia as a wartime cession of land thatwas valid according to international law.
The map shows the scope of Japanʼs territories. As Japan is surrounded by sea, the extent of
its territory on land is small. However, its exclusive economic zones (EEZ) is the 11th biggest in

Scope of the Peripheral Islands Territory of Japan(source: Ministr y of Foreign Affairs of Japan, https://www.mofa.go.jp/
territory/index.html)
21
Japan Review Vol.3 No.2 Fall 2019

Debates Concerning the Incorporation of Peripheral Islands into the Territory of Japanthe world. The existence of the Ogasawara Islands is why international law recognizes a vast EEZ
for Japan. The EEZ is likely to become an economically promising area because of the wealth ofunderwater resources that have been discovered in the zone.

1. Acquisition of Island Territories in the Pacific by Occupation
The Ogasawara Islands
The Ogasawara Islands are island territor y under the jurisdiction of Tokyo Metropolisthat includes the Ogasawara Islands, the Volcano Islands, Okinotorishima Island, andMinamitorishima Island. According to the official website of Ogasawara Village, the Ogasawara
Islands were so named because Ogasawara Sadayori landed on one of its islands and put up awooden marker in 1593. He then reported what he had done to the Tokugawa Shogunate. The
islands remained unoccupied and uninhabited for some time after this, but a great number ofships started coming here in the 1800s. Two Americans, a British person, an Italian, and a Danesettled here with some Kanakas from Hawaii in 1830. Commodore Matthew Perry of the U.S.
Navy also landed here in 1853. It appears that many ships in distress drifted here around 1830, sothat the islands became inhabited by people of different nationalities.
From the 1860s, Japanese people started colonizing and settling the islands in earnest, using
the Ogasawara Islands as a waystation to the South Sea Islands. The Edo shogunate sent aninspection team to set up a provisional government office in 1862, and accepted immigrants
from Hachijojima Island. Difficulties in the colonization process led all of the Japanese to be
evacuated the following year. In 1876, the Japanese government enacted regulations that were to
be enforced on the Ogasawara Islands, set up a government office on the islands, and notified theambassadors of foreign countries in Tokyo that the Ogasawaras would be placed under Japanesejurisdiction.
Germany, France, the Netherlands, and Spain replied that they would abide by Japanʼ sdecision. The U.S. and Britain objected on grounds that their citizens had extraterritorial rights.
Following exchanges of letters between the Japanese government and the two countries, they
acknowledged the Japanese measures. The Ogasawara Islands became Japanese territor ythrough occupation, on the basis of other countriesʼ explicit or implicit acknowledgement ofJapanʼs announcement that it was taking possession of the islands.

The Volcano Islands (Iwojima Island)
The Volcano Islands, also known as Iwojima Island, were known to Europeans since the 17th
century and were left as an unoccupied territory possessed by no country. In 1889, Tanaka Eijiro
and more than a dozen other settlers landed on the islands to fish and carry out sulfur mining.
The cultivation of crops such as sugar cane, coca, and lemons later became the islandsʼ mainindustry. In 1891, the Tokyo prefectural government requested the national government to makeexplicit its jurisdiction over the Volcano Islands to manage the Japanese who were there.
The central government named by imperial decree the three islands belonging to the Volcano
Island chain Kitaiwo Island, Iwo Island, and Minamiiwo Island. The islands were placed under thejurisdiction of the Ogasawara Island government of Tokyo Prefecture by a decision of the cabinetthat was made public. There were no objections to the Japanese governmentʼs decision fromother countries, so Japan acquired the three islands through occupation.
The number of permanent residents of the Volcano Islands subsequently rose to about 1,000.
The outbreak of World War II led to the evacuation of the residents to mainland Japan in 1944.
There exists a Japanese Maritime Self-Defense Force base on Iwojima Island, but none of theformer residents have returned.

22Japan Review Vol.3 No.2 Fall 2019

Takai Susumu

Okinotorishima Island
Twenty to thirty years ago, Okinotorishima Island used to be a much larger rock than it is today,
but it has shrunk to become a small rock due to seawater erosion. Okinotorishima Island as
identified as an islet called Parece Vela on sea charts from the 17th century, but was left as an
uninhabited island in no countryʼs possession. The Japanese government deemed OkinotorishimaIsland an unoccupied territory in July 1931 and placed it under the jurisdiction of Ogasawara
Subprefecture by a notice from the Ministry of Home Affairs. There were no objections to theJapanese government ʼs act from other countries, so Japan acquired Okinotorishima Island
through occupation.
Seawater erosion caused Kitakojima Island and Higashikojima Island to become
Okinotorishima Islandʼs only reefs that were sticking out of the water at high tide. To preventthe submerging of the reefs, the government conducted conservation work on two occasions
between 1987 and 1993.

Minamitorishima Island

Minamitorishima Island is located far from the Japanese archipelago and is Japanʼs easternmost
island territory. In the 1860s, not only exploration ships but also whalers appeared in the waters
around Minamitorishima Island, and a great number of ships recorded the existence of theuninhabited island that came to be called Minamitorishima Island.
Mizutani Shinroku, who drifted to Minamitorishima Island during a storm in 1896, saw
that it was rich in resources, and so led 23 people from the Ogasawara Islands to settle on
Minamitorishima Island and carry out business activities. As Mizutani made a request to lease
the island from the Japanese government in 1898, the government decided to take possessionof Minamitorishima Island and incorporated the island into Japanese territory by a notice from
Tokyo Prefecture in July 1898. Japan took possession of Minamitorishima Island by occupation.
In 1902, Mizutani founded Mizutani Village, where about 60 Japanese settled and conductedactivities such as collecting guano, carr ying out taxidermy, and canning food. The island
currently has no civilian residents. When Commodore Perr y of the U.S. Navy came to the
Ogasawara Islands, he recommended to his government that the U.S. should take possession of
Minamitorishima Island. Since the U.S. government had no interest in Minamitorishima Island, it
did not challenge Japanʼs territorial rights.

2. Acquisition of Island Territories in the Sea of Japan and the East China Sea
Takeshima
Takeshima in the Sea of Japan consists of the two islets Ojima Island and Mejima Island.
Takeshima has been well known to Japanese people since the Edo period, when it was called
Matsushima Island. West of Matsushima Island is Ulleungdo, which was then called Takeshima,and many records show that the Murakawa family and the Otani family of Tottori Domain made afortune by developing the island after obtaining permits to travel there from the Edo shogunate.
Matsushima Island was used as a place to disembark and rest on route to Ulleungdo.
The Korean government subsequently asked, via its Communication Envoys, the Edo
shogunate to prohibit travel to Ulleungdo so that no Japanese could go there and develop theisland. The shogunate was also informed of Koreaʼs empty-island policy that kept Koreans fromsettling on Ulleungdo. The shogunate had adopted a seclusion policy, so it accepted the Koreanrequest and prohibited Japanese from traveling to Ulleungdo. However, Matsushima Island was
not subject to this travel ban.
A British ship “discovered” a non-existent island to the west of Ulleungdo in the latter halfof the 18th century using unsophisticated surveying technology. The phantom island ended up
23
Japan Review Vol.3 No.2 Fall 2019

Debates Concerning the Incorporation of Peripheral Islands into the Territory of Japan

being marked on sea charts, leading to Western maps including three islands in the area: the nonexistent island, Ulleungdo, and Matsushima Island. When Western maps were imported to Japanin the latter half of the 19th century, the non-existent island came to be called by the name ofTakeshima and Ulleungdo started to be called by the name of Matsushima Island, which caused
confusion.
In response to a request to lease Matsushima Island from Nakai Yozaburo in 1905, theJapanese cabinet decided in January 1905 that the Matsushima Island of the Edo period should
be renamed Takeshima because Ulleungdo was called Matsushima Island by Japanese people atthat time. The cabinet also decided that Takeshima should be listed in the register of state-owned
land and placed under the jurisdiction of Shimane Prefecture. Nakai Yozaburo leased Takeshimafrom the government for 30 years and conducted activities such as gathering abalone and hunting
sea otters.
With the outbreak of World War II, people stopped fishing around Takeshima. After the end of
the war, in 1952, the South Korean president unilaterally proclaimed a maritime zone over which
South Korea exercised sovereignty, arguing that Takeshima, or Dokdo in Korean name, was
Korean territory.
The Japanese government protested the Korean moves. South Korea ignored the protest
and illegally occupied Takeshima by force in 1954, and the island remains under South Korean
occupation.

The Senkaku Islands
The Senkaku Islands in the East China Sea are a group of islands. Around 1885, the Japanese
government ordered the navy to begin surveying the Senkaku Islands, and civilian exploration
teams also landed on the Senkakus. When a man named Koga Tatsushiro asked to lease theSenkaku Islands in 1894, the government formally incorporated them into Japanese territory byoccupation of terra nullius through a cabinet decision handed down in January 1895. This wasdone after it was verified that the islands were not under the control of the Qing dynasty or any
other country. Koga and about 200 other people engaged in activities such as harvesting yakogai
seashells, processing bonito, and catching albatross for their down. Following the 30-year lease
period, the Senkaku Islands were sold to Koga Tatsushiroʼs son, Zenji, and became private land.
After World War II, the Senkaku Islands were placed under U.S. administration together with
Okinawa in accordance with the San Francisco Peace Treaty. China protested against the UnitedStates action arguing that Okinawa, a part of the Japanese territories should not be administeredby the United States. However, when the existence of oil deposits in the waters around the
Senkaku Islands became known in 1969, China began asserting in 1970 that the islands were
Chinese territor y. The islands were returned to Japan in accordance with the 1972 Okinawa
Reversion Agreement.

3. Acquisition of Island Territories in the Sea of Okhotsk through MutualConsent
The Northern Territories
The status of the Islands and Sakhalin Island in the Sea of Okhotsk has been determined throughthe mutual agreement of Japan and Russia. Japan and Russia signed the 1855 Treaty of Commerceand Navigation, which drew up an international border between Urup Island and Iturup Island.
The Russian czar believed his nationʼs territory extended to the southern tip of Urup Island. So
the 1855 treaty had the effect of confirming an existing border rather than drawing up a new
boundary.
The treaty did not draw up a border for Karafuto (Sakhalin) Island, and left the island under
24
Japan Review Vol.3 No.2 Fall 2019

Takai Susumu

joint Russo-Japanese control. The two nations later concluded the Treaty of St. Petersburg in
1875, which made the Kurils a Japanese territory and Sakhalin Island a Russian territory. Eachstateʼs territorial rights over the respective islands took shape through territorial exchanges,
which were mutually agreed acts of the cessation of land in peacetime.
In 1905, the two countries concluded the Treaty of Portsmouth, which brought an end to the
Russo-Japanese War. Japan acquired Sakhalin Island south of the 50th parallel through a mutuallyagreed act of cessation following the end of hostilities.
At around the end of World War II, about 400,000 Japanese lived on Sakhalin Island and about
17,000 on the Kuril Islands. The islanders enjoyed prosperous livelihoods. With the defeat ofJapan in 1945, the Soviet Union advanced south along the islands from the Kamchatka Peninsula
to Urup Island to disarm the troops stationed in the Japanese territor y of the Kuril Islands.
Meanwhile, troops were dispatched from Vladivostok to disarm Japanese soldiers on the HabomaiIslands, Shikotan Island, Kunashir Island, and Iturup Island. Subsequently, the inhabitants ofthe four islands were forcefully deported to Hakodate in Hokkaido via Sakhalin Island. After theJapanese departure, Russians settled on the islands, and remain to this day.

4. Japan’s Island Territories according to the San Francisco Peace Treaty

After Japanʼs defeat in World War II, the scope of the nationʼs territories was defined by the
San Francisco Peace Treaty. With Japanʼs acceptance of the Alliesʼ Potsdam Declaration, whichstated the conditions for ending the war, World War II came to a close. The Potsdam Declaration
declared that Japanʼs sovereignty and extent of its territories should be decided by the Allies,
but at the same time, it stated that the Cairo Declaration would be upheld. The Cairo Declaration
proclaimed that the Allies did not fight Japan with the aim of expanding their own territories, andthat they would make Japan relinquish what it had obtained through “violence and greed.” The
Allies drew up the territorial clauses of the 1951 Peace Treaty on the basis of preceding texts.
The territorial clauses in Article 2 of the San Francisco Peace Treaty stipulated that Japan
should recognize Korean independence and renounce all right, title, and claim to Korea;
renounce all right, title, and claim to Taiwan and the Pescadores; and renounce the Kuril Islands
and southern Sakhalin Island.

5. The Territorial Clauses in the San Francisco Peace Treaty and the Objections
against Them
The Ogasawara Islands

The Alliesʼ decision on the extent of Japanese claims to territorial sovereignty was made clear
in the San Francisco Peace Treaty. Article 3 of the treaty stipulates that the Ogasawara Islandsin the Pacific should be placed under a trusteeship, with the U.S. as the sole administrator. The
Ogasawara Reversion Agreement was concluded between Japan and the U.S. in 1968, and theIslands were returned to Japan. The Ogasawaras marked the 50th anniversary of their reversion
to Japan in 2018.

Takeshima
South Korea objected to how the San Francisco Peace Treaty treated Takeshima. Its argument
was that Takeshima, or Dokdo in Korean name, has been a Korean territor y since ancient
times, and that it was part of Korean territory that was renounced by Japan in the San Francisco
Peace Treaty. We should note here that South Korea was not a signatory to the treaty. It waslater revealed that during the drafting of the agreement, a Korean ambassador to the U.S.
had requested the United States to explicitly stipulate to include Dokdo as part of the Korean
25
Japan Review Vol.3 No.2 Fall 2019

Debates Concerning the Incorporation of Peripheral Islands into the Territory of Japanpeninsula that was to be renounced by Japan, but this request was rejected.
As part of their occupation policy, the Allies defined what came to be known as the MacArthurLine. The demarcation of the line was based on SCAPIN (Supreme Commander for the AlliedPowers Instruction Note) 677 and 1033, which serve to narrow the Japanese scope of activities.
South Korea asserted that the Allies had acknowledged Takeshima as South Korean territory
because it was on the South Korean side of the MacArthur Line. SCAPIN 677 and 1033 statedthat the line had been temporarily set up as part of occupation policy, and specified that the line
was not to be construed as being a final territorial determination, but South Korea ignored thesecaveats.
South Korea issued a proclamation on its maritime sovereignty in January 1952, just before
the San Francisco Peace Treaty came into effect. This proclamation asserted that Dokdo, called
Takeshima by Japan, was South Korean territory. The declaration drew up what was called theSyngman Rhee Line along the MacArthur Line, which was set to disappear once the occupationof Japan ended.
Japanese fishing boats started operating in the waters around Takeshima after World War II,
but were seized by South Korean patrol ships one after the other. Japan strongly protested theseizures of Japanese fishing boats and asserted that Takeshima was Japanese territory, whilestrongly objecting to the South Korean Syngman Rhee Line. South Korean maritime police
forcefully occupied Takeshima by force in 1954, and they remain to this day.

The Senkaku Islands
The Senkaku Islands were placed under U.S. trusteeship together with Okinawa in accordancewith Article 3 of the San Francisco Peace Treaty, and it was returned to Japan in 1972 under the
stipulations of the Okinawa Reversion Agreement. However, China asserts that the Senkaku
Islands were discovered by China and so was part of Taiwan, which was renounced by Japanaccording to Article 2 of the San Francisco Peace Treaty.
In 2012, China announced that the Senkaku Islands are core interest. The core interests
asserted by China are Chinese territories that are to be reclaimed, even if militar y force isrequired. Taiwan, Tibet, Xinjiang, and the South China Sea were identified as core interests
in 2009. However, with the expansion of the core interests to include the Senkaku Islands in
2012, China set up the East China Sea Air Defense Identification Zone in the airspace above theSenkakus, announcing that all civil aircraft passing through the zone would be required to fulfill
certain obligations.
The Japanese government purchased the privately owned Senkakus and made them stateowned in 2012. China strongly opposed what it perceived as a Japanese attempt to claim Chinese
territory, and sent ships to patrol the waters around the islands and started to claim that they
were policing fishing activities. Japan argued that it had simply bought the Senkaku Islands
from private sector owners, but China continued to argue that Japan had stolen and nationalized
Chinese territory. The situation remains deadlocked today.

The Northern Territories
The Soviet Union refused to sign the San Francisco Peace Treaty on grounds that the Northern
Territories that were to be renounced by Japan, according to Article 2 (c) of the treaty, were nottransferred to the Soviet Union. The Soviet Unionʼs intention to acquire the Northern Territories
as spoils of war through cessation did not work out. The three Allied leaders―British Prime
Minister Churchill, U.S. President Roosevelt, and Soviet Premier Stalin―had signed the Yalta
Agreement in February 1945. The agreement promised that the Kuril Islands would be handed
over to the Soviet Union and that the USSR would regain control over Sakhalin Island after WorldWar II. The Soviet Union asserted that the Northern Territories were a part of the Kuril Islands
26Japan Review Vol.3 No.2 Fall 2019

Takai Susumu

and were Soviet because of the stipulations of the Yalta Agreement. The status of the Territories
remains unchanged as of this day.
The Soviet Union and Japan subsequently agreed to a declaration that would end the state ofwar between the two states. Moscow aimed to end the war and secure the peace as quickly as
possible, while Tokyo sought the swift return of Japanese soldiers interned in Siberia. The result
was the Soviet-Japanese Joint Declaration of 1956. In this declaration, the Soviet Union promised
to transfer the Habomai Islands and Shikotan Island to Japan as an expression of the goodwill of
its people. After the conclusion of the Treaty of Mutual Cooperation and Security between the U.S.
and Japan in 1960, the Soviet Union made the removal of U.S. military bases in Japan a condition
for the return of Habomai Islands and Shikotan Island.
Prime Minister Shinzo Abe and President Vladimir Putin are engaged in diplomaticnegotiations about the conclusion of a definitive peace treaty, taking into consideration that it isunprecedented to not have concluded such a treaty more than 70 years after the end of hostilities.
Questions such as whether a peace treaty can even be concluded, whether the treaty will haveclauses providing for the return of Habomai Islands and Shikotan Island, and whether the treaty
will touch upon the return of Kunashir Island and Iturup Island are attracting attention.
As we have seen, Japan has come to possess island territories in accordance with internationallaw. Japanʼs peripheral islands such as the Ogasawara Islands in the Pacific Ocean, the Senkaku
Islands in the East China Sea, and Takeshima in the Sea of Japan have been incorporated into
the countryʼs territory after title was obtained through occupation under international law. The
Northern Territories in the Sea of Okhotsk have been incorporated into Japanese territory bymutually agreed treaties. However, Russia and Japan have different interpretations of thesetreaties.

27
Japan Review Vol.3 No.2 Fall 2019