Drilling for Independence: Minamitorishima as Japan's Bid to Break China's Grip on Critical Minerals

Minamitorishima is Japan's easternmost territory, the only island east of the Japan Trench. It is a coral atoll of roughly 1.5km2, covered in trees, grass, and little else besides a species of gecko and large colonies of seabirds. It is administratively part of Ogasawara, a municipality governed as part of the Tokyo metropolis. From the nearest inhabited Japanese island, it is still over 1200 kilometres away. Under international law, every island generates a 200-nautical-mile Exclusive Economic Zone. Minamitoroshima's EEZ reaches deep into the Central Pacific, projecting Japanese sovereign economic rights across an enormous area of open ocean, including the seabed directly beneath it. 

Illustration by The Geostrata

GUANO, WARSHIPS AND A FORGOTTEN ISLAND

In 1896, a Japanese fisherman named Mizutani Shinroku was swept by chance onto a barren strip of coral rising barely nine meters above the Pacific. This was a remote speck of land 1,950 kilometers southwest of Tokyo, small enough to cross on foot in minutes. He raised a claim for Japan. What followed was a farcical dispute over guano, in simpler words, accumulated droppings of seabirds that coastal nations had long prized as fertiliser.

An American captain, Andrew Ambrose Rose Hill, sailed to contest the claim of the island and to enforce guano rights only to find a Japanese warship already waiting. Japan kept the island, installed settlers, buried 191 soldiers there during the Second World War, handed it to the Americans in 1985 and got it back in 1968 as part of diplomatic choreography preceding the return of Okinawa. By 2009, the transmitting station that had kept the island technically useful was switched off, made redundant by GPS. The only inhabitants left were a rotating Self-Defence Force detachment and meteorologists. 

Minamitorishima, also called Marcus Island, seemed headed for the obscurity that swallows most uninhabited Pacific atolls, but then a research team from the University of Tokyo went looking for fish bones. The geology of what lies beneath that seabed is worth understanding. The process begins with the ocean’s dead. Fish carcasses settle on the seafloor, where their bones and teeth, which are dense with calcium phosphate, break down over geological timescales. The resulting phosphatic sediment draws in rare earth elements drifting through seawater. Over tens of millions of years, the accumulation compounds.

The resulting deposits sit roughly 10 m below the sea floor, but the sea floor itself is approximately 6000 m underwater.

 Analytical results from early sampling showed that the maximum rare earth content in the Minamitorishima mud reaches 6,600 parts per million, which is 20 to 30 times higher than the ion absorption type deposits in Southern China. 

In 2012, Professor Yasuhiro Kato of the University of Tokyo confirmed the existence of large-scale deposits within Japan’s EEZ. Mud samples taken from the seabed around 5,600 metres down indicate deposits equivalent to around 220 times the average annual amount used by Japanese industry, with dysprosium, a critical element for hybrid and electric vehicle motors, being among the most concentrated.

By 2018, the research group had visualized the three-dimensional distribution of rare-earth-rich mud across a 2,500 km² research area, estimating the total resource amount at more than 16 million tons of earth oxides. These are not just light rare earths, like cerium and lanthanum, that can be found in scattered deposits elsewhere. The deposits carry an estimated 730 years’ worth of dysprosium and 420 years’ worth of terbium for Japan's current consumption levels.

The rare earth mud around Minamitorishima has a 50:50 ratio of heavy to light earths, unlike Chinese deposits that are roughly 25:75. It is precisely the heavy rare earths where China's dominance has few serious challengers.

THE SHOCK THAT FOCUSED JAPAN'S MIND

Japan did not come looking for rare earth out of geological curiosity. It came because of an incident in September 2010 that exposed a structural vulnerability it could not afford to ignore. On 7 September 2010, a Chinese fishing boat collided with two Japanese coastguard vessels of the Senkaku Islands in the East China Sea. The coastguard arrested the captain.

Among China's responses was stopping the export of rare earth minerals to Japan. Without any formal announcement, Chinese customs officials began holding back rare earth shipments bound for Japan, using the leverage of market dependency to press Tokyo into releasing the detained captain. The vulnerability it revealed was stark. Japan had relied primarily on China for its imports of rare earth metals, with 89.1% of Japan's total imports coming from China in 2009. China, at the same time, roughly controlled 90% of the world's rare earth supply.

The episode became the foundational case study in the weaponisation of the critical mineral supply chain. Japan began diversifying immediately, signing supply deals with Australia and Brazil, investing in refining facilities in Vietnam, and building recycling infrastructure at home. In 2012, a research team from the University of Tokyo and other institutions discovered rare earth deposits on the seabed around Minamitorishima, and the island’s significance was immediately understood within the broader context.

FROM DISCOVERY TO EXTRACTION

The engineering challenge is steep. The sediment sits only 10 metres below the seafloor, but that seafloor is 6,000 metres underwater. The viable method is pipeline lifting: a seabed machine converts ore into a slurry, which is pumped to the surface, dewatered, and shipped to mainland Japan for acid-based extraction. The project has spent 40 billion yen since 2018 through Japan’s Strategic Innovation Promotion Program.

In February 2026, JAMSTEC demonstrated continuous pumping from 6,000 metres depth near Minamitorishima. Prime Minister Takaichi declared Japan would never have trouble with rare earths again. Whether that confidence is warranted remains contested. Deep-sea mining costs far exceed land-based alternatives, and separation involves over 200 complex steps.

A 2021 analysis put the net present value of a 15-year project at a $525 million loss. One genuine advantage here is the presence of deposits inside Japan’s EEZ, allowing it to bypass the International Seabed Authority entirely, letting Tokyo set its own environmental terms. 

Environmental risk is the other unresolved variable. Pipeline lifting disturbs the seafloor and kicks up sediment plumes that can suffocate marine life for weeks. Japan's closed mining configuration is designed to suppress plume dispersion and limit noise and light pollution at depth, with assessments conducted continuously throughout the trial. How much damage the method causes at commercial scale remains an open question regulators will need to answer before any production decision is made.

WHY IT MATTERS NOW

The timing of the 2026 extraction test was not incidental. On January 6, 2026, China targeted Japan with new export restrictions on dual-use technologies, including rare earth elements, permanent magnets and critical minerals for defence production. This is widely seen as a response to Prime Minister Takaichi’s comments suggesting a Chinese attack on Taiwan could constitute an existential threat to Japan. 

The pattern is repeating.

As of 2024, Beijing still accounted for more than 60% of Japan's total rare earth imports despite more than 15 years of active diversification. A three-month curb on Chinese rare earth exports could cost Japanese businesses 660 billion yen and shave 0.11% of annual GDP, according to Nomura Research Institute.

If the 2026 trial proves successful, a full-scale mining operation could begin as early as February 2027, targeting 350 metric tons of rare earth-rich mud per day. The technology is also transferable, as Japan holds an ISA exploration contract for International waters near Hawaii, and the pipeline lifting method has applications for other seabed metals like cobalt, nickel, manganese, and copper. But extraction is only the beginning. China's dominance is not primarily geological. It lies in separation, chemistry, refining capacity, and magnet manufacturing. Even a successful extraction effort would not break that bottleneck without equivalent downstream investment.

Minamitorishima is best understood as an insurance policy. It's expensive, uncertain, and long-horizon, but a genuine hedge against the kind of coercion that the last two decades have shown is entirely available to Beijing. For Japan, a country without significant offshore mineral resources, the 6000-metres gamble is what industrial policy looks like when the alternative is permanent vulnerability.

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BY NISHQA

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