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Minamitorishima (南鳥島; lit. "Southern Bird Island") sometimes Minami-Tori-shima or Minami-Torishima, also known as Marcus Island, is an isolated Japanese coral atoll in the northwestern Pacific Ocean, located some 1,848 km (998 nmi; 1,148 mi) southeast of Tokyo and 1,267 km (684 nmi; 787 mi) east of the closest Japanese island, South Iwo Jima of the Volcano Islands, and nearly on a straight line between mainland Tokyo and Wake Island, 1,415 km (764 nmi; 879 mi) further to the east-southeast. The closest island to Minamitorishima is East Island in the Mariana Islands, which is 1,015 km (548 nmi; 631 mi) to the west-southwest.

Key Information

It is the easternmost territory belonging to Japan, and the only Japanese territory on the Pacific Plate, past the Japan Trench. Although small (151 ha or 370 acres),[1] it is of strategic importance, as it enables Japan to claim a 428,875-square-kilometre (125,040-square-nautical-mile) exclusive economic zone in the surrounding waters. It is also the easternmost territory of Tokyo, being administratively part of Ogasawara Subprefecture. No civilians live there, except personnel of the Japan Meteorological Agency, Japan Self-Defense Forces (JSDF), and Japan Coast Guard serving temporary tours of duty on the island.[2]

Access

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The island is off limits to civilians except for Japan Meteorological Agency staff, although reporters, documentary makers, and scientific researchers can sometimes get an entry permit. No commercial boat tours or flights visit the island, and civilians are currently not allowed access to Minamitorishima for tours or sightseeing, due to its use by the JSDF as an observation station.[2]

Geography and geology

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Map of Minamitorishima

Minamitorishima is very remote. There is no other land for over 1,000 km (540 nmi; 621 mi) in any direction.

The island is triangular in shape, and has a saucer-like profile, with a raised outer rim of between 5 and 9 m (16 and 30 ft) above sea level. The central area of the island is 1 m (3 ft) below sea level. Minamitorishima is surrounded by fringing reefs, which range from 50 to 300 m (164 to 984 ft) in width, enclosing a shallow lagoon, which is connected with the open ocean by narrow passages on the southern and northeastern sides.

Outside the reef, the ocean depths quickly plunge to over 1,000 m (3,300 ft). The island has a total land area of 1.51 km2 (1 sq mi).[1] It takes about 45 minutes to walk around the island.

The sea is clear in the shallow area around Minamitorishima. At night, no light pollution occurs, so rarely noticed stars are clearly visible in the sky.[2]

The island does not have soil adequate to produce substantial crops, so food is brought in by supply ships and planes. The only food grown on the island is papaya, mustard greens, and coconuts, and saltwater fish are caught offshore.[2]

Minamitorishima area rare-earth deposits

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After China restricted exports of strategic rare-earth oxides (REOs) in 2009, Japan started to explore its seabeds for deposits.[3]

In January 2013, a deep-sea research vessel of the Japan Agency for Marine-Earth Science and Technology obtained seven deep-sea mud core samples from the seafloor at 5,600 to 5,800 m depth, about 250 km (130 nmi; 160 mi) south of the island.[4] The research team found a mud layer 2 to 4 metres (6.6 to 13.1 ft) beneath the seabed that is extremely concentrated in REO. Analytical results showed that the maximum REO content in the mud was up to 0.66%.[5][6]

In 2018 a scientific study of the seabed mud resulted in an estimate of 16 million tons of REO mineralised sediments within the studied area. The calculated rare-earth element and yttrium content for the research area was more than 16 million tons (average = 964 ppm).[7][8]

Wildlife

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A species in the gecko family Gekkonidae, Perochirus ateles, inhabits the island. In Japan, these are found only in Minamitorishima and South Iwo Jima. They are thought to have arrived from Micronesia on driftwood.[citation needed]

Also, a large number of land snails, Achatina fulica, have parasites that are harmful to humans. Various forms of marine life inhabit the ocean around the island, including sea snakes, tuna, sharks, and some rare fish. Small fish are in the shallow area around the island.[2]

Population

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No local residents live on Minamitorishima. Civilians are not allowed to reside there, and the personnel of the Japan Meteorological Agency, JSDF, and the Japan Coast Guard, only serve on the island for a limited time, and in limited numbers.[2]

History

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Japan's exclusive economic zones: Minamitorishima is at the center of the isolated easternmost circle.
  Japan's EEZ
  Joint regime with Republic of Korea
  EEZ claimed by Japan, disputed by others

First known sightings

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The first discovery and mention of an island in this area was made by a Spanish Manila galleon captain, Andrés de Arriola, in 1694.[9] It was charted in Spanish maps as Sebastián López, after Spanish Admiral Sebastián López, victorious in the battles of La Naval de Manila in 1646 against the Dutch. Its exact location was left unrecorded until further sightings in the 19th century.

Captain Bourn Russell (1794–1880) in the Lady Rowena departed Sydney, NSW, 2 November 1830 on a Pacific whaling voyage. On his return on 27 June 1832, he reported an island, not on his charts, which he named "William the Fourth's Island". The Sydney Herald reported Russell's description of the size, shape, and orientation of the island and its reef, but misspelled his name and gave the island a Southern Hemisphere latitude.[10]

The island was sighted again on 16 December 1864 by Captain Charles Gelett of the Hawaiian Evangelical Association's missionary ship Morning Star, and was called "Weeks Island" by him. Its position was recorded by a United States survey ship in 1874 and first sighted by a Japanese national, Kiozaemon Saito, in 1879.[11][12][13]

Colonization and sovereignty contention

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On 30 June 1886, Japanese explorer Shinroku Mizutani [ja] (水谷新六, 1850–1921) led a group of 46 colonists from Haha-jima in the Bonin Islands to settle on Marcus Island. The settlement was named "Mizutani" after the leader of the expedition. The Empire of Japan officially annexed the island 24 July 1898,[14] the previous United States claim from 1889 according to the Guano Islands Act not being officially acknowledged. The island was officially named "Minamitorishima" and placed administratively under the Ogasawara Subprefecture of Tokyo (Tōkyō-fu).[citation needed]

Sovereignty over the island before World War I was apparently disputed, as various sources from the time move the island from the American to Japanese domain without specific explanation. In 1902, the United States dispatched a warship from Hawaii to enforce its claims, but withdrew on finding the island still inhabited by Japanese, with a Japanese warship patrolling nearby. In 1914, William D. Boyce included Marcus Island as an obviously American island in his book, The Colonies and Dependencies of the United States. In 1933, by orders of the Japanese government, the civilian inhabitants of Minamitorishima were evacuated. In 1935, the Imperial Japanese Navy established a meteorological station on the island and built an airstrip.[citation needed]

World War II

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Minamitorishima under attack on 31 August 1943

After the start of World War II, the Japanese garrison stationed on the island consisted of the 742-man Minamitorishima Guard Unit, under the command of Rear Admiral Masata Matsubara, and the 2,005-man 12th Independent Mixed Regiment of the Imperial Japanese Army, under the command of Colonel Yoshiichi Sakata.[15] The United States Navy bombed it repeatedly in 1942[16] and in 1943,[17] but never attempted to capture it (the island was featured in the U.S. film The Fighting Lady). Japan was able to resupply the garrison by submarine, using a channel, still visible today, cut through the reef on the northwest side of the island. The island was subject to repeated U.S. air attacks during World War II, and finally surrendered when the destroyer USS Bagley arrived on 31 August 1945.[18]

U.S. occupation

[edit]
Minamitorishima in 1975

The Treaty of San Francisco transferred the island to American control in 1952.[a] The island was returned to Japanese control in 1968, but the Americans retained control of the airstrip and LORAN-C station.[citation needed]

In 1964, after some delays caused by storms that ravaged the island during construction, the U.S. Coast Guard opened a LORAN-C navigation station on Minamitorishima, whose mast was until 1985 one of the tallest structures in the Pacific area at 411 metres (1,350 ft). Before replacing Loran A for general marine navigation, Loran C was used by submarine-launched Polaris missile systems and the existence and location of Loran C stations was classified. LORANSTA Marcus Island was billeted for 23 US Coast Guard personnel. The commissioning commanding officer was U.S. Coast Guard Lieutenant Commander Louis. C. Snell. A detachment of SeaBees remained on the island for several months making repairs to the island's airstrip.[citation needed]

The island is extremely isolated. Coast guardsmen stationed on the island served one-year tours that were later modified to allow an R&R visit to mainland Japan at the six-month point. At the end of this isolated tour of duty, crew members received an additional 30 days of compensatory leave.[citation needed]

While under U.S. administration, a C-130 Hercules from the 345th Tactical Airlift Squadron, Yokota Air Base, Japan, resupplied the island on missions every Thursday. Coast guardsmen often amused themselves by judging aircraft landings, raising placards painted with large numbers. An unusually long four-hour ground time was scheduled to allow technicians who flew in to perform maintenance on the transmitter and to offload extra fuel from the C-130 to power the island's generator. It also allowed the coast guardsmen to read and answer letters while aircrews snorkeled and collected green glass fishing buoys that had washed up on the shore. During the Vietnam War era, the weekly log flight[further explanation needed] was a DC-6 flight conducted by the CIA-operated "Air America."[citation needed]

Resumed Japanese administration

[edit]

The Marcus Island station was transferred from the U.S. Coast Guard to the Japan Maritime Self Defense Force (JMSDF) on 30 September 1993 and was closed on 1 December 2009.[citation needed]

The island is currently used for weather observation and has a radio station, but little else. The JMSDF garrison was supplied by C-130s from Iruma Air Base, or by C-130s from Haneda or Atsugi Air Base with flights via Iwo Jima on a weekly basis. The runway of Minami Torishima Airport is only 1,300 m (4,300 ft) long and cannot handle large aircraft.[citation needed]

Climate

[edit]

Minamitorishima has a tropical savanna climate (Köppen climate classification Aw), with warm to hot temperatures throughout the year. The wettest months are July and August, while the driest months are February and March. It has the highest average temperature in Japan of 25 °C (77 °F).[19] Temperature extremes range from 13.8 °C (56.8 °F) on February 10, 1976 to 35.6 °C (96.1 °F) on July 17, 1951.

Climate data for Minami-Torishima (1991−2020 normals, extremes 1951−present)
Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Record high °C (°F) 29.7
(85.5) 		29.0
(84.2) 		30.2
(86.4) 		31.9
(89.4) 		34.0
(93.2) 		35.0
(95.0) 		35.6
(96.1) 		34.7
(94.5) 		35.3
(95.5) 		33.5
(92.3) 		34.2
(93.6) 		31.6
(88.9) 		35.6
(96.1)
Mean daily maximum °C (°F) 24.6
(76.3) 		24.3
(75.7) 		25.3
(77.5) 		27.1
(80.8) 		29.0
(84.2) 		31.0
(87.8) 		31.3
(88.3) 		31.0
(87.8) 		30.9
(87.6) 		30.2
(86.4) 		28.7
(83.7) 		26.7
(80.1) 		28.3
(82.9)
Daily mean °C (°F) 22.4
(72.3) 		21.8
(71.2) 		22.5
(72.5) 		24.3
(75.7) 		26.1
(79.0) 		28.0
(82.4) 		28.5
(83.3) 		28.4
(83.1) 		28.5
(83.3) 		27.9
(82.2) 		26.5
(79.7) 		24.5
(76.1) 		25.8
(78.4)
Mean daily minimum °C (°F) 20.3
(68.5) 		19.6
(67.3) 		20.4
(68.7) 		22.3
(72.1) 		24.1
(75.4) 		25.8
(78.4) 		26.1
(79.0) 		26.1
(79.0) 		26.4
(79.5) 		25.9
(78.6) 		24.7
(76.5) 		22.6
(72.7) 		23.7
(74.7)
Record low °C (°F) 13.9
(57.0) 		13.8
(56.8) 		14.2
(57.6) 		16.4
(61.5) 		19.1
(66.4) 		20.0
(68.0) 		21.6
(70.9) 		21.8
(71.2) 		21.7
(71.1) 		20.8
(69.4) 		19.2
(66.6) 		16.7
(62.1) 		13.8
(56.8)
Average precipitation mm (inches) 69.7
(2.74) 		43.4
(1.71) 		56.0
(2.20) 		59.6
(2.35) 		100.6
(3.96) 		44.3
(1.74) 		139.8
(5.50) 		177.1
(6.97) 		94.8
(3.73) 		89.6
(3.53) 		83.0
(3.27) 		90.8
(3.57) 		1,052.8
(41.45)
Average precipitation days (≥ 0.5 mm) 10.9 8.5 8.1 7.8 9.3 7.2 14.8 16.7 14.1 12.7 10.4 11.8 132.7
Average relative humidity (%) 70 70 74 79 79 77 77 79 79 78 76 74 76
Mean monthly sunshine hours 170.8 179.4 222.3 240.2 275.1 311.2 276.3 248.1 254.6 250.8 211.0 182.3 2,821.7
Source: Japan Meteorological Agency[20]

See or edit raw graph data.

See also

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Notes

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References

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Further reading

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[edit]
Revisions and contributorsEdit on WikipediaRead on Wikipedia

Minamitorishima

View on Grokipedia
from Grokipedia
Minamitorishima, also known as Marcus Island, is a remote coral atoll in the northwestern Pacific Ocean that marks Japan's easternmost territory. Located at approximately 24°17′N 153°59′E and about 1,848 kilometers southeast of Tokyo, it belongs administratively to Ogasawara Village in Tokyo Metropolis and features a low-lying land area of roughly 1.2 square kilometers with no permanent civilian inhabitants. The island supports a meteorological observation station operated by the Japan Meteorological Agency and facilities of the Maritime Self-Defense Force, staffed by around 23 personnel on rotation. Its strategic position enables Japan to claim an exclusive economic zone exceeding 400,000 square kilometers, encompassing vast seabed deposits of rare-earth elements in muds—estimated at 16 million tons of rare-earth oxides—and polymetallic nodules totaling hundreds of millions of tons, positioning it as a key asset for resource security amid global supply dependencies. Historically, a meteorological station and airfield were established there in 1935 by the Imperial Japanese Navy; during World War II, it endured U.S. air attacks, and post-war administration shifted to the United States until reversion to Japan in 1968.

Geography

Physical Features

Minamitorishima constitutes Japan's easternmost territory, positioned approximately 1,848 kilometers southeast of in the western and administered as part of within Tokyo Metropolis. The island lies entirely on the tectonic plate, situated beyond the . As a , Minamitorishima encompasses a land area of roughly 1.5 square kilometers and features flat terrain with a maximum of 9 meters above . It is encircled by fringing reefs, 50 to 300 meters wide, that enclose a shallow linked to the surrounding , while the seafloor descends abruptly to depths of about 1,000 meters just beyond the reefs. The island's remote oceanic setting underpins Japan's claim of approximately 430,000 square kilometers in the adjacent waters, bolstering the nation's extensive Pacific maritime domain.

Geology and Mineral Resources

Minamitorishima is an isolated atoll formed atop a subsiding volcanic , or , in the northwestern , where tectonic has allowed growth to cap the eroded summit with formations up to several meters thick. The underlying structure reflects intraplate on the Pacific Plate, distant from active subduction zones, resulting in a low-relief platform surrounded by steep submarine slopes descending to abyssal depths exceeding 5,000 meters. Seabed surveys within Japan's (EEZ) around the have identified deep-sea mud layers highly enriched in rare earth elements (REEs), including and , at concentrations surpassing 5,000 parts per million (ppm) total rare earth elements plus yttrium (REY) in hydrogenetic sediments derived from seamount-hosted sources. In 2013, a University of Tokyo-led expedition discovered REY-rich mud at depths of around 5,600 meters, with peak values reaching 6,600 ppm just three meters below the sediment surface at site PC05, attributed to adsorption onto biogenic phosphates and ferromanganese oxyhydroxides. These deposits span areas south and east of the island, with geochemical analyses classifying sediments into chemostratigraphic units marked by REY enrichment peaks linked to paleoceanographic conditions favoring accumulation. Resource estimates for the EEZ indicate at least 16 million metric tons of recoverable REY metal content, potentially extending to vastly larger "semi-infinite" volumes based on expansive low-grade halos, offering a strategic counter to concentrated foreign supplies dominated by . Polymetallic nodules, composed primarily of ferromanganese crusts, occur in dense fields on nearby seamounts approximately 300 kilometers east and 1,800 kilometers southeast of Minamitorishima, containing accessory REEs alongside primary , , and , with surveyed nodule abundances supporting totals of around 230 million dry metric tons.

Climate and Environment

Climate Patterns

Minamitorishima exhibits a classified as Aw under the Köppen system, characterized by warm temperatures year-round and a pronounced . The annual mean temperature is 25.4 °C, with monthly averages exceeding 20 °C throughout the year based on 1981–2010 normals from the (JMA). Daily temperatures typically range from 22 °C to 30 °C, with relative consistently high at 75–85% due to its isolated oceanic position, contributing to persistent salt-laden air that accelerates on metallic structures and equipment used in meteorological and operations. Precipitation totals approximately 1,050–1,100 mm annually, concentrated in the from July to January, while February to June averages less than 50 mm per month, defining the dry period. The island's location in the western North Pacific exposes it to frequent passages, with several systems annually tracking within 150 km, intensifying rainfall and winds during the June–October peak season; JMA records indicate variable impacts, such as enhanced from systems like Neoguri in 2025. Extreme events include recorded lows of 13.8 °C in February 1976 and highs of 35.6 °C, though such deviations are rare given the stable maritime influence. JMA observations, maintained since the mid-20th century at the island's station (WMO ID 47991), document these patterns, underscoring challenges for sustained operations like and disruptions that limit to short-term rotations.

Wildlife and Marine Ecosystems

Minamitorishima, a remote atoll, supports sparse terrestrial dominated by , with no native mammals recorded. Empirical surveys indicate breeding populations of tropical such as the (Phaethon rubricauda), alongside historical presence of white terns (Gygis alba) and Christmas shearwaters (Puffinus nativitatis), though recent observations note declines possibly due to or habitat pressures. communities, including land crabs that process , contribute to cycling, while consists primarily of introduced grasses and shrubs adapted to saline, -enriched soils, with limited endemic due to the atoll's isolation and small land area of approximately 1.5 square kilometers. Marine ecosystems surrounding the feature well-developed fringing coral reefs in shallow waters, harboring diverse assemblages including small reef species, tunas, and sharks, alongside . These reefs, though underexplored owing to the island's remoteness 1,940 kilometers southeast of , sustain migratory pelagic species and support Japanese fisheries under national wildlife protection laws, which designate certain seabirds like the (Phoebastria albatrus)—observed in the vicinity—as nationally protected. Detailed inventories remain limited, with surveys confirming presence of rare but lacking comprehensive species counts for turtles or other reptiles specific to the atoll. Deeper seabed habitats within Japan's around Minamitorishima host polymetallic nodule fields rich in , , and , covering extensive areas and providing microhabitats for deep-sea . Surveys have identified 27 of benthic organisms at nodule sites, including zoanthids (7 across 8 orders) and galatheoid crustaceans, which rely on nodules for oxygenation and in oxygen-minimum zones. These nodules, estimated at over 230 million tonnes in the region, underpin unique deep-sea life cycles, though extraction proposals raise concerns over disruption without resolved causal data on recovery. Japanese law governs such areas under broader marine resource frameworks, prioritizing empirical assessment over exploitation.

Human Presence

Population and Facilities

Minamitorishima maintains no permanent civilian population, with occupancy restricted to temporary personnel rotating in for operational duties. Staff primarily consist of observers and members focused on monitoring and security tasks. As of April 2010, approximately 23 personnel were stationed on the island, though numbers fluctuate with mission requirements and resupply cycles. Key facilities support self-contained operations amid the island's isolation, including a observatory for continuous atmospheric and measurements, contributing essential data to national and environmental tracking systems. The Maritime Self-Defense Force maintains barracks and oversees a functional for operations, alongside a for periodic supply vessel deliveries that sustain provisions, fuel, and equipment. These installations enable ongoing scientific vital to Japan's and climate research infrastructure, with personnel rotations ensuring continuity without establishing residency. Access remains limited to authorized agency workers, underscoring the island's role as a specialized outpost rather than a habitable settlement.

Access and Infrastructure

Access to Minamitorishima is severely restricted due to its remote position approximately 1,950 kilometers southeast of , with no commercial flights or civilian vessel services permitted. The island's sole , Minami Torishima Airbase, operates a single spanning the atoll's length, primarily accommodating government-operated aircraft for personnel rotation, meteorological resupply, and emergency logistics; flight durations from average around four hours under favorable conditions. Maritime access relies on infrequent supply ships and patrol vessels departing from Chichi-jima in the Ogasawara Islands, located about 1,200 kilometers northwest, with transit times extending four to five days amid variable Pacific weather patterns that often include typhoons and high swells. These voyages deliver essential goods, fuel, and equipment to sustain the small resident staff, underscoring the logistical challenges of the island's isolation. Infrastructure on the island centers on functional facilities enabling sustained operations, including communication towers for weather data transmission and tide gauges integrated into the Meteorological Agency's network for and maritime surveillance. These installations, supplemented by basic docking points for resupply vessels, face ongoing constraints from corrosive saltwater exposure, seismic activity, and seasonal storms, necessitating regular maintenance via air-dropped or shipped materials.

History

Early Discovery and Exploration

The earliest recorded mention of an island in the position of Minamitorishima appears in the log of Spanish Manila galleon captain Andrés de Arriola, who sighted land during a trans-Pacific voyage on December 6, 1694, at approximately 24°16'N, 153°58'E. This sighting, charted on subsequent Spanish maps as "La Isla del Buen Socorro," has been identified by some historians as Minamitorishima, though debates persist over precise coordinates and whether it refers to the same due to navigational inaccuracies of the . Earlier claims of a 1543 sighting by Spanish explorer Bernardo de la Torre exist but lack confirmatory matching the island's location at 24°17'N, 153°59'E, rendering them inconclusive. By the mid-19th century, American maritime interest prompted systematic surveying; a vessel recorded the island's position in 1874, naming it Marcus Island after a or ship, and noting its low-lying structure visible from afar. Japanese records indicate the first national sighting in 1879 by Kiozaemon Saito, a seaman whose observations from passing vessels contributed to initial charting efforts. These empirical logs emphasized the atoll's isolation, approximately 1,848 km east-southeast of , with no signs of prior human habitation. Initial landings in the early 1880s, such as that by Japanese mariner Tsunetaro Shinzaki in November 1883 aboard a British vessel, confirmed the uninhabited status through on-site inspections, revealing thick guano deposits up to several meters deep—valuable as amid global demand. Explorers documented the island's saucer-shaped , fringed by reefs and supporting dense populations, but found no sources or suitable for sustained human presence beyond resource extraction. Shinroku Mizutani's 1886 voyage further assessed guano viability via sample collection and mapping, relying on ship logs that underscored the atoll's potential economic value without evidence of indigenous activity.

Colonization and Sovereignty Claims

In 1889, Captain Andrew Rosehill, aboard the whaler Nassau, landed on the uninhabited island, hoisted the flag, and filed a discovery claim in a bottle, invoking the of to assert potential U.S. territorial rights due to suspected deposits. This claim lacked subsequent formal endorsement or effective control by the U.S. government, which did not dispatch officials or settlers to administer the territory. Japanese trader Mizutani Shinroku shipwrecked on the island in 1896 during a trading voyage, identifying substantial resources and petitioning the Japanese government for a to exploit them. On July 19, 1898, Japan's formally named the island Minamitorishima, and on July 24, 1898, the annexed it through official incorporation, treating it as —unclaimed land under international law at the time—and establishing via intent and initial acts of possession. The government granted Mizutani a 10-year starting December 1898 for extraction, leading to the establishment of Mizutani Village in May 1902 as a settlement hub with approximately 58 residents engaged in mining and bird collection. The U.S. claim was resolved through early 20th-century ; by 1908, U.S. correspondence affirmed no American territorial assertion and explicitly recognized Japanese , prioritizing effective Japanese administration over the prior informal hoisting of a flag. Minamitorishima was administratively integrated into under the Ogasawara , demonstrating continuous Japanese control through resource development and governance despite the island's extreme remoteness, over 1,800 kilometers from . This occupation aligned with prevailing international legal principles requiring animus occupandi (intent to possess) and corpus occupandi (effective control), unhindered by competing assertions lacking material enforcement.

World War II Events

Minamitorishima, referred to as Marcus Island by Allied forces, was fortified by as a and airfield base during the , supporting reconnaissance and resupply operations via submarines despite isolation. The initial U.S. offensive action against the island occurred on March 4, 1942, when Task Force 16, under William F. Halsey Jr., launched dive bombers and torpedo planes from USS Enterprise to strike airfield facilities and anti-aircraft positions, accompanied by naval gunfire from cruisers USS Salt Lake City and USS Northampton that destroyed fuel and ammunition stores. Subsequent raids intensified pressure on the Japanese garrison, which numbered around 742 personnel at the war's outset and relied on resupply amid U.S. interdictions of convoys. On August 31–September 1, 1943, carrier aircraft from Task Group 15.1, including USS Saratoga and USS Princeton, conducted a major airstrike, bombing runways, hangars, and defenses, resulting in the destruction of several seaplanes and significant infrastructure damage. U.S. submarines also shelled the island periodically between 1942 and 1944, targeting fortifications and supply points to disrupt operations without committing to invasion. In May 1944, Task Group 58.6, part of the , executed another airstrike on May 19–20, further neutralizing the airfield amid the broader campaign, though the island's remote position led to its bypass in the U.S. strategy of selective island-hopping to prioritize central Pacific advances. By late 1944, repeated attacks had rendered the base largely inoperable, with defenses abandoned following Japan's surrender. The garrison formally surrendered on August 31, 1945, aboard USS Bagley (DD-386), experiencing minimal casualties due to the absence of ground combat.

Post-War Occupation and Return to Japan

Following Japan's surrender on September 2, 1945, the Imperial Japanese garrison on Minamitorishima was repatriated, and the island came under administration as part of the Allied occupation of Japanese territories. The U.S. military utilized the island primarily for navigational and training purposes, including the construction of a (Long Range Aid to Navigation) radio station by the U.S. in 1964 to support maritime and aviation operations in the Pacific. The legal basis for U.S. control was formalized in Article 3 of the , signed on September 8, 1951, and effective April 28, 1952, which granted the administrative authority over Minamitorishima (referred to as Marcus Island) pending any trusteeship arrangement, while retained residual sovereignty over the Nanpo Shoto group. During this 23-year period of U.S. oversight, no permanent civilian population resided on the island, and access was restricted to , emphasizing its role in low-profile strategic support rather than full territorial incorporation. On June 26, 1968, under the bilateral Agreement Between Japan and the United States of America Concerning the Bonin Islands and Other Islands, administrative control of Minamitorishima was returned to Japan alongside the Ogasawara (Bonin) Islands, affirming Tokyo's sovereignty without conditions that implied ongoing U.S. territorial claims. Post-reversion, Japanese authorities shifted focus to civilian scientific applications, establishing a meteorological observation station to monitor weather patterns in the remote Pacific and an auxiliary airfield for supply flights, marking the transition from military exclusivity to regulated research and environmental monitoring. This handover resolved the temporary administrative arrangement under the 1951 treaty, with the U.S. retaining limited access rights only for the existing LORAN facility to ensure navigational continuity.

Strategic and Economic Significance

Military and Geopolitical Role

Minamitorishima hosts a small detachment of the (JMSDF), consisting of approximately 12 personnel, tasked with surveillance and protection of Japan's easternmost in the . The island also features an auxiliary air facility operated by the (JASDF), supporting regional monitoring operations. In July 2024, the (JGSDF) announced plans to construct a missile firing range on the specifically for testing the upgraded Type 12 surface-to-ship missile, which extends operational range to about 1,000 kilometers to enable standoff defense capabilities. This development represents Japan's first such range on its remote territories, aimed at enhancing anti-ship deterrence amid escalating regional threats. Geopolitically, Minamitorishima's position as Japan's eastern frontier underpins maritime jurisdiction over an (EEZ) of approximately 429,000 square kilometers, significantly expanding Japan's strategic footprint in the central Pacific. This EEZ assertion strengthens Japan's overall projection and supports the U.S.-Japan framework by facilitating extended surveillance and rapid response options against potential adversaries. The island's isolation and lack of civilian population make it ideal for defense infrastructure that bolsters national posture without domestic constraints.

Rare Earth Deposits and Mining Initiatives

Surveys conducted in 2024, including efforts from April to June investigating nearly 100 locations within Minamitorishima's surrounding , have confirmed substantial (REE)-rich mud deposits at depths exceeding 5,000 meters. These findings build on post-2010s explorations, estimating over 16 million tons of REE-rich mud in a limited surveyed area alone, with broader potential extending across the zone. As a national project led by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), a test mission was conducted from January 12 to February 15, 2026, using JAMSTEC's deep-sea drilling vessel Chikyu to retrieve REE-rich mud from depths of approximately 5,500 to 6,000 meters, with successful mud recovery operations from January 30 to early February. This initiative involves collaborations with the National Institute of Advanced Industrial Science and Technology (AIST), Kyoto University, Kochi University, and other state entities, as well as industry-academia partnerships. Private firms, such as Toyo Engineering, provide contracted technical support for the design and manufacturing of mud recovery systems, but no single company oversees the overall mining operations. The project focuses on developing extraction technologies and assessing feasibility, with a full-scale mining test planned for February 2027 targeting up to 350 tons/day and a profitability/feasibility report due by March 2028. The strategic rationale emphasizes national in critical minerals, mitigating risks from China's dominance in global REE (over 90%) and (around 70%), thereby securing supply chains for technologies like electric vehicles and renewables without relying on land-based alternatives prone to geopolitical disruptions. However, estimates from the Dai-ichi Life Economic Research Institute and others indicate that the cost of rare earth elements from Minamitorishima mud, including mining, transportation, and refining, is approximately 70,000 USD per ton—about 20 times higher than Chinese rare earth concentrate at around 3,600 USD per ton—highlighting significant commercialization challenges despite the planned test mining in 2026. Deep-sea methods offer potential advantages in reduced surface pollution compared to terrestrial , aligning with empirical assessments prioritizing resource independence.

Controversies and Debates

Environmental Impacts of Development

Development around Minamitorishima, particularly prospective extraction of (REE)-rich seabed mud, poses risks of localized disturbance through sediment plumes generated during operations at depths exceeding 5,000 meters. These plumes could temporarily smother benthic and alter water chemistry in nodule and mud fields, potentially leading to among slow-recovering deep-sea species. However, empirical studies indicate that affected ecosystems in such abyssal environments exhibit partial recoverability over decadal timescales, contrasting with the persistent from terrestrial REE mining, which releases radioactive and into soils and waterways at concentrations up to 10 times higher than deep-sea mud sources. In 2025, environmental advocacy groups raised alarms over Japan's planned near the , citing potential irreversible harm to marine habitats from sediment resuspension and mobilization. Countervailing assessments, including Japan's Environmental Impact on Seamounts (DIETS) , demonstrate that surface waters and pelagic fisheries experience negligible impacts due to the operations' depth confinement, with monitoring protocols tracking plume dispersion via acoustic and chemical sensors. Japanese domestic regulations under the Ministry of Economy, Trade and Industry mandate pre- and post-extraction environmental baselines, including surveys and sediment assays, absent binding international standards for coastal REE mud zones. Causal evaluations of extraction trade-offs reveal that REE yields from Minamitorishima's —estimated at 1.2 billion tons sufficient for centuries of global —facilitate advancements in magnets and defense electronics, yielding a lifecycle 90% lower than land-based alternatives when accounting for avoided terrestrial and . Localized deep-sea effects, while warranting rigorous mitigation, do not scale to the widespread ecological degradation observed in China's Bayan Obo mines, where drainage has contaminated 1,000 square kilometers of grasslands.

Sovereignty and International Relations

Minamitorishima, also known as Marcus Island, was formally incorporated into Japanese territory by a cabinet decision on January 16, 1899, following earlier surveys and extraction activities by Japanese interests starting in the . American explorations in the , including visits by vessels like the USS Peacock in 1840, prompted initial uncertainty over control, but no formal territorial challenge materialized, and Japan's assertion prevailed under international norms of effective occupation at the time. Unlike Japan's contested claims over the or Northern Territories, Minamitorishima has faced no active sovereignty disputes from neighboring states. Following Japan's defeat in , Minamitorishima came under administration as part of the Pacific Islands Trust Territory in 1945, but was returned to Japanese sovereignty on June 26, 1968, alongside the Ogasawara (Bonin) Islands, per agreements reflecting the island's unambiguous pre-war Japanese control and lack of indigenous populations or rival claims. This reversion affirmed Japan's title without litigation, distinguishing it from prolonged post-war occupations elsewhere. Japan's sovereignty enables its (EEZ) around Minamitorishima, spanning approximately 420,000 square kilometers and ratified under the Convention on the (UNCLOS) to which acceded in 1996. While the island's EEZ itself encounters no direct overlaps with foreign claims, has opposed 's 2008 submission to the UN Commission on the Limits of the Continental Shelf seeking extension beyond the 200-nautical-mile limit near Minamitorishima, producing reports to contest the geological basis and hinder resource development. These efforts reflect broader Chinese maritime expansionism rather than challenges to the island's incorporation or UNCLOS-compliant EEZ generation. maintains its rights through diplomatic engagements and technical submissions, emphasizing empirical seabed data over unsubstantiated objections. In , leverages Minamitorishima's status for strategic partnerships, including resource exploration collaborations with the to secure critical minerals within its undisputed EEZ, underscoring sovereign exploitation prerogatives absent in disputed areas. Such counters narratives of vulnerability by demonstrating effective control and compliance with global maritime law, without necessitating concessions to expansionist pressures from non-riparian states.

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