Japan is going to the depths of the ocean to reduce its reliance on China.
Tokyo has launched an ambitious plan to mine the floor of the Pacific for mud rich in rare earth minerals at a depth of 6km.
One of Japan's icons, Mt Fuji, is just under 3.8km high.
The plan has been years in the making but comes at a precarious time, with diplomatic relations between Tokyo and Beijing at a low ebb.
China continues to ramp up pressure on Japan, after Prime Minister Sanae Takaichi suggested Tokyo could react militarily to any attack on Taiwan.
Beijing claims the self-ruled island and has not ruled out taking it by force.
Here is what we know about the plan, Japan's reliance on critical minerals and why this is happening now.
Where is Japan mining?
On Monday, the Japanese scientific drilling vessel Chikyu set sail for the remote island of Minami-Torishima in the Pacific.
The Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has touted the test as a world first at such depths.
It will attempt to lift mud continuously off the seabed and onto the ship.
The area around the island is believed to contain massive amounts of rare earth minerals, which are used to make everything from electric vehicles to hard drives, missiles and wind turbines.
Environmental groups and Pacific nations have raised significant concerns about seabed mining, including habitat destruction, the contamination of food chains with heavy metals and sediment plumes.
However, the Japanese government and researchers have argued the process is in some ways cleaner than land-based rare earth mining, including that it produces less radioactive by-products.
[MAP]Program director Shoichi Ishii said it was hoped the Minami-Torishima mission would pave the way for domestic production of rare earths.
"We are considering diversifying our procurement sources and avoiding excessive reliance on specific countries," he said as the ship prepared to leave.
He didn't say which country Japan was trying to reduce its reliance on, but experts agree there's one that fits the bill.
China.
Why is Japan mining the seabed?
Currently, Tokyo imports more than 70 per cent of its rare earths from China, according to the Japan Organization for Metals and Energy Security.
China is by far the biggest supplier of rare earths globally.
But last week, amid growing tensions around Japan's position on Taiwan, China's commerce ministry announced a strengthening of "export controls on dual-use items to Japan", effective immediately.
The dual-use list was comprised of technology, goods or software that has both civilian and military use.
Some rare earths were included on the list but details were vague.
The Wall Street Journal reported that China was already tightening restrictions on rare earths and rare-earth magnets.
Tokyo said late last week that it was monitoring the situation.
Takahide Kiuchi, executive economist at Nomura Research Institute, said the impact on the Japanese economy would be "extremely severe" if China included rare earths in export controls.
He estimated that a three-month ban could cost Japan 660 billion yen ($6.2 billion) and reduce the nation's gross domestic product by 0.11 per cent.
"Particularly for rare earths like dysprosium and terbium, which are auxiliary materials for neodymium magnets used in EV [electric vehicle] motors, Japan is said to depend almost 100 per cent on China," he added.
Is the plan viable?
The area around Minami-Torishima, which is in Japan's economic waters, is estimated to contain more than 16 million tonnes of rare earths, which the Nikkei business daily reported is the third-largest reserve globally.
These rich deposits contain an estimated 730 years' worth of dysprosium, used in high-strength magnets in phones and electric cars, and 780 years' worth of yttrium, used in lasers, Nikkei said.
The mining project has so far cost Tokyo 40 billion yen ($376 million) since 2018.
However, key aspects remain unknown including the quality of the minerals.
Mining the mud had previously been seen as too expensive to be viable.
Kotaro Shimizu, principal analyst at Mitsubishi UFJ Research and Consulting, said it could be viable in coming years if China continues to disrupt supply and buyers become willing to pay higher prices.
The Japanese vessel, with 130 crew and researchers, is scheduled to return to port on February 14.
If the initial expedition is successful, a full-scale mining trial will be conducted in February 2027.
Japan hopes to commercialise rare earths from 2030.
Rare earths 'strategically vital' for Japan
Takahiro Kamisuna researches the geoeconomics of critical minerals and Japan's defence and foreign policies in the Indo-Pacific for the International Institute for Strategic Studies (IISS).
He told the ABC it was "strategically vital" that Japan reduced its reliance on China given the export controls placed on rare earths following Ms Takaichi's remarks on Taiwan.
"As we have seen … defence and economic security have become increasingly inseparable," he said.
"The growing geopolitical tension with China has changed the perception of Tokyo on the rare earths supply chain as the weight has shifted from economic efficiency to economic security."
He cautioned that it remained to be seen if the mining technology would work and the quality of the minerals mined.
He said if it did, it could open up other benefits for Japan on top of its own rare earths supply chain.
"Japan might be able to share stockpiles of rare earths from Minami-Torishima with its allies in the future, which will be a strong diplomatic instrument," he said.
ABC/wires
