As military tensions between China and Japan reach the highest level in more than a decade, a sparsely populated Japanese island finds itself right on the front line.

Sitting just 110 kilometres east of Taiwan, Yonaguni marks the tail end of an archipelago stretching north to Japan’s main islands, a distance roughly equivalent to the length of the California coastline. Ever since Nancy Pelosi’s trip to Taipei in 2022 as the US House speaker prompted China to fire missiles that landed near Yonaguni, Japan has accelerated plans for its largest military build-up in at least four decades.

Up and down the 160-strong Ryukyu island chain, Japan is quickly putting in place missile batteries, radar towers, ammunition storage sites and other combat facilities. It’s also beginning to deploy major military assets on Kyushu, the southernmost of Japan’s four main islands, including F-35 fighter jets and long-range missiles, as well as expanding its version of the US Marine Corps, known as the Amphibious Rapid Deployment Brigade.

The race to fortify the islands is raising the stakes of the current spat between Asia’s biggest economies, as Beijing ramps up pressure to force Japanese Prime Minister Sanae Takaichi to retract remarks suggesting that Japan might deploy its military if China one day attempts to seize Taiwan. Over the weekend, a Chinese fighter aircraft locked its weapons-targeting radar on Japanese warplanes, showing the risk of miscalculation if tensions persist.

“China’s People’s Liberation Army is undoubtedly building up its ability to force Taiwan into submission,” said Koichi Isobe, a former lieutenant general in Japan’s Ground Self-Defence Force. “Japan, the United States, and other Western countries must show China their strong resolve to oppose any actions that seek to change the status quo.”

A subtropical island known mostly for endangered wild horses and dive spots with hammerhead sharks, Yonaguni now has apartment buildings sprouting up to house troops for a military base established in 2016. Over the next year, some 30 staff will join the nearly 230 already onsite to accommodate an electronic warfare division, and more are expected to follow with the planned deployment of anti-air missiles.

Some of the 1500 or so residents on the island are becoming more nervous at the infusion of arms, and have sought more clarity from Japanese officials on plans. On a warm evening earlier this month, about 80 locals gathered at a community hall for an “explanation meeting”, at which Defence Ministry officials explained why it was necessary to deploy troops, anti-air missiles and weapons that use electromagnetic waves to jam enemy communications and targeting capabilities.

Some residents voiced concerns over the dangers of an enhanced military presence, with one saying Takaichi should have kept quiet. But others, such as Shigeru Yonahara, a 63-year-old car mechanic and town council member, agreed with the Defence Ministry’s position. A few days before the meeting, Japan’s military reported that it spotted a suspected Chinese drone near the island.

“Right now we’re defenceless,” Yonahara said in an interview. “We need the electronic warfare unit to disable threats like drones.”

Japan is installing weapons such as this type 03 Chū-SAM surface-to-air missile on its southern islands.JGDSF

Since Takaichi’s remarks triggered a backlash from China, she has repeatedly asserted that Japan hasn’t changed its policy toward Taiwan or made any new commitment on when it might deploy its military. However, her remarks have highlighted how closely the security of Japan and Taiwan is connected.

While Japan maintains a doctrine of strict self-defence, in 2015 the government of then-prime minister Shinzō Abe oversaw a landmark legal change that allowed the military to aid friendly nations in a situation where Japan’s own survival could also be at stake. Before Takaichi took power in October, Abe and successive leaders had avoided giving specific scenarios under which “collective self-defence” would be applied, aware that doing so might stoke tensions with China.

But in private, government officials and security analysts have long mentioned that one scenario could be an American-led defence of Taiwan, given Japan’s proximity to the island democracy and its own dependence on the US for security. Any prospect that American forces would fail to stop a Chinese invasion of Taiwan would therefore inevitably put Japan’s own security at risk.

Japan would have little choice but to support the US in a conflict regardless of how it is viewed by Tokyo, according to Kyoko Hatakeyama, a former Japanese government analyst who is now a professor of international relations at Niigata University.

“If we decline the US request, that would mean the end of the alliance,” she said. “And the United States might not even protect Japan in the case of China’s attack on Japan.”

The military build-up has attracted heated debate in parliament. Last month, the head of Japan’s opposition Communist Party said the government’s defence plans were creating a “missile archipelago”. Defence Minister Shinjiro Koizumi has rejected that description, saying Japan was deploying its forces in line with other countries. During a recent visit to Yonaguni, he said plans to deploy medium-range surface-to-air missiles on the island were intended to reduce the likelihood of attacks on Japan.

Japanese Defence Minister Shinjiro Koizumi speaks during a visit to Yonaguni last month.Bloomberg

Tension over Taiwan has its origin in agreements that ended World War II – a history that Chinese President Xi Jinping is now seeking to bend to his advantage. In conversations with US President Donald Trump and other leaders, Xi has argued that China helped defeat Japan, and that two wartime statements – the Potsdam Declaration and the Cairo Declaration – made clear that Beijing has sovereignty over Taiwan.

As part of its response, some Chinese officials have indicated that World War II-era declarations also raise doubts about Japan’s sovereignty over Yonaguni and other islands in the Ryukyu chain. Last month, Chinese Foreign Ministry spokesman Lin Jian posted on X a quote from the 1945 Potsdam Declaration, which said Japanese sovereignty should be limited to the country’s four main islands, “and such minor islands as we determine”.

‘After 80 years, it’s come to this. Are they going to make Okinawa a battlefield once again?’

Protester Hiroyuki Teruya

Japan, the US and Taiwan reject China’s assertions, pointing to the San Francisco Peace Treaty as a legally binding agreement. Signed in 1951 by Japan and almost 50 allied nations, the treaty states that Tokyo “renounces all rights, title and claim” to Taiwan, but doesn’t specify to whom. It also placed the Ryukyu Islands under US administration, paving the way for American military bases primarily located on the island of Okinawa. The islands were returned to Japan in 1972.

US forces invade Okinawa in April 1945. Thousands of Japanese civilians were killed in the final major land battle of the Pacific war.AP

Beijing rejects the San Francisco treaty, and the Chinese embassy in Tokyo last month posted that it was merely an “invalid scrap of paper”. China retains active claims to the Senkaku Islands, known as the Diaoyu Islands to Beijing, which sit to the north of Yonaguni. Those islands fall under the US-Japan mutual defence treaty, a position that Trump’s envoy to Japan, George Glass, reaffirmed last month.

China has also sought to play on tensions between indigenous islanders and the militaries of both Japan and the US. Last month, Chinese state-run tabloid Global Times appeared to call for Ryukyu independence in a Weibo post, saying “only the Ryukyu people themselves can decide the fate of Ryukyu”.

A prominent Chinese state media journalist also questioned Japan’s sovereignty over the islands in a 12-minute television segment, saying they were “turned into a huge military base with its indigenous people forced to endure deep-rooted discrimination”.

Those debates are most prevalent on Okinawa, the centre of American and Japanese military power on the archipelago, where major US Marine Corps and other military bases would likely provide the first response in any conflict over Taiwan if Washington chooses to intervene. Japan is also building up its own military presence on the island: last year, it inaugurated an anti-ship missile base that serves as a command centre for similar outposts on the islands of Ishigaki, Miyako and Amami-Oshima.

Hiroyuki Teruya, a 73-year-old former college professor, has led demonstrations against a Japanese missile base in the city of Uruma on Okinawa. He worries that the militarisation of Japan’s southern islands will lead to a repeat of the Battle of Okinawa in 1945, the final land offensive by the US in the Pacific War that resulted in the deaths of tens of thousands of civilians.

All three of Teruya’s uncles were killed in that conflict. Plans for evacuation shelters on Japan’s southern islands were a hopeless attempt to protect locals against new bloodshed, Teruya said. Rather than trying to deter China and preparing for conflict with a stronger military, Japan should prioritise diplomacy to avoid war, he said.

“After 80 years, it’s come to this,” he said. “Are they going to make Okinawa a battlefield once again?”

Japan’s pacifism challenged

Historical memories remain a strong influence on older Japanese, who identify more closely than younger generations with Japan’s post-World War II rejection of militarism. In 1947, Japan adopted a pacifist constitution that remains unchanged to this day.

The increased military presence on Yonaguni could make it a “high priority” target for China in the event of war.Getty Images

Younger Japanese, however, are largely supportive of Japan’s military build-up. A poll conducted by the Sankei newspaper and Fuji News Network on November 22–23 found that 83.2 per cent of respondents aged between 18 and 29 supported Takaichi’s plans to increase defence spending – nearly double that of those Japanese older than 70. Takaichi has pledged to reach defence spending worth 2 per cent of gross domestic product this fiscal year, two years ahead of schedule.

Okinawa has a far higher concentration of military bases than any other prefecture in Japan, most of them American. Ayako Arakaki, a local lawmaker in the ruling Liberal Democratic Party, said that widely held perceptions that Okinawans were opposed to bases are inaccurate. Arakaki said that the sound of fighter jets scrambling from a base near her office in response to Chinese military activity near Japan is a reminder of the challenge.

“China has long made claims that are out of step with the international community, completely disregarding the consensus in Japan,” said Arakaki, referring to Chinese statements on the sovereignty of Japanese islands. “What we’re seeing is a country that won’t accept anything unless its own demands are met.”

If Japan plays a supporting role in any US-led defence of Taiwan, the new electronic warfare unit on Yonaguni could transform the island from a passive observation post into an active “kill chain” enabler that could feed precise targeting data to Japanese and US missile batteries, according to Franz-Stefan Gady, an adjunct fellow at the Centre for a New American Security, a Washington-based research group. That could make it a key priority for China, he said, and made the island a “high-priority target for early neutralisation”.

Kenichi Itokazu, Yonaguni’s former mayor, has called for the islands defences to be beefed up.AFR

On Yonaguni, the debate over Japan’s military presence came to a head in a mayoral election this summer. The victor, Tsuneo Uechi, campaigned on a more cautious approach to the build-up, replacing a hawkish incumbent. In an interview, Uechi said he accepted that existing plans for electronic warfare and medium-range anti-air missile units would help defend the island, and he also welcomed the arrival of younger people from the military on an island where most people are much older.

Still, he said, further moves to install anti-ship batteries like those positioned on other islands would add to local “psychological stress”, he said. The meeting between the Defence Ministry and residents this month came in response to Uechi’s request to the government for more openness about its plans.

“These developments are not intended to attack any other country,” Kouzou Shimo, a Japanese Defence Ministry official, told residents at the meeting. “It is purely for us to defend ourselves in a crisis.”

The previous mayor, Keniichi Itokazu, says Takaichi didn’t go far enough in indicating her support for Taiwan. He wants additional missile systems on Yonaguni and joint military exercises involving Japanese, US and Taiwanese forces.

“Japan alone cannot defend itself,” Itokazu said. “The US-Japan alliance creates the deterrence that prevents China from making moves toward Taiwan or the Ryukyus.”

Bloomberg

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