‘Only thunder, no rain’ is the Chinese saying.

Plenty of serious-sounding noise has come from Japan in the past few years about the need to back Taiwan against conquest by China, but it isn’t turning into much practical security cooperation.

Taiwan’s lack of such collaboration with its great democratic neighbour leaves the island with less than optimal defence preparation. Also, anything that would make Taiwan more secure against China would also make Japan safer.

‘There are … areas where Taiwan really, really needs Japan,’ a Taiwanese security insider says. ‘And to some extent Japan really needs Taiwan.’

There should be ‘cooperation on a wider range of issues that involve security,’ that person says, citing ‘supply chain security and traditional military security—even just having an entry-level exchange of intelligence that concerns national security.’

Among the world’s politicians, former Japanese leaders have made some of the most enthusiastic declarations of support for Taiwan over the past few years.

Late prime minister Shinzo Abe said in 2021 that Japan and the United States could not stand by if China attacked Taiwan. ‘A Taiwan emergency is a Japanese emergency and therefore an emergency for the US-Japan Alliance,’ he said. Abe went on to call for the US to ditch its policy of strategic ambiguity, which leaves Beijing guessing about Washington’s possible response to attempted conquest of the island, and instead make it clear it would defend it.

Last year, former prime minister Taro Aso said Japan should ‘be the very first one’ to show it had capabilities that could defend Taiwan.

Prominent strategic documents, including Japan’s annual defense white paper and National Security Strategy, in the past few years have begun listing peace and stability in the Taiwan Strait as important to Japan’s own security. Japan last year quietly appointed a serving government official to its Taiwanese de facto embassy to act as a military attache.

The Japan Forum for Strategic Studies for the first time has invited think tankers from Taiwan to attend a tabletop exercise simulating a conflict in the Taiwan Strait. Whether it had an official okay in doing this isn’t clear.

These developments reflect Tokyo’s growing worries about China’s massive rearmament under Chinese leader Xi Jinping and Beijing’s intentions to build sufficient capabilities to forcefully take Taiwan through an invasion or blockade. Taiwan lies 111km west of Japan-administered Yonaguni Island and 170km southwest of the Senkaku islands, Japanese ownership of which is disputed by China.

If China attacked or blockaded Taiwan, its forces would very likely intrude into Japan’s airspace and waters, potentially dragging Tokyo into a war over the island democracy. A cross-strait war could also potentially involve attacks on US bases in Japan and disrupt Japanese commercial shipping. In 2022, Japan relied on imports, such as crude oil and natural gas, for 97 percent of its energy supply.

Perhaps the greatest issue, however, is that seizure of Taiwan would mean China would own part of first island chain, which stretches from Japan to Indonesia and restricts China’s access to the Pacific. With the island under its control, China’s naval and air forces could range over the ocean without having to pass so close to potentially hostile territory on their way out and back. That would increase the threat to Japan.

So, reasons for Japanese security cooperation with Taiwan are obvious, and authoritative voices in Japan are calling for it. But Japan has still rejected Taiwanese requests for formal security cooperation, even at a rudimentary level. Even unofficial security ties between the two countries look hard to develop.

There is now some frustration in Taiwanese security circles, where officials say exchanges of retired generals and defence think-tankers cannot act as a substitute for direct contact and coordination between the two nations’ militaries.

In 2019 former president Tsai Ing-wen publicly asked for direct dialogue with the Japanese government over cyberspace and regional security issues, saying it was important for them to share information in real time about Chinese military movements. Japan was indifferent.

Lack of cooperation means, for example, that Taiwan’s air force cannot coordinate with Japan’s on where each would defend airspace in the event of war with China. The two countries are not developing military equipment together. And they don’t take the opportunity to improve the performance of their forces by exercising with each other.

Why is Japan dragging its feet? Extensive Japanese business exposure to China is one obvious reason, and another is Beijing’s diplomatic heft. ‘Japan still feels pressure from China,’ Lii Wen, now Taiwan’s presidential spokesperson, said in an interview earlier this year. ‘Japan’s foreign ministry will feel the pressure more acutely,’ he said. Lii was then head of international affairs for the Democratic Progressive Party, the party of President Lai Ching-te.

Japanese bureaucracy is conservative and therefore much less inclined to change policy on Taiwan than members of parliament are. The ruling Liberal Democratic Party’s Abe faction, a typically pro-Taiwan group, may have lost influence since some of its members were punished in April by a disciplinary committee over a political funding scandal.

Whereas the United States has its Taiwan Relations Act, Japan has no legal basis for security interactions with the island, which, under the one-China policy, it does not recognize as a country.

Japan also faces significant constitutional restrictions on taking military action. Altogether, then, it clearly prefers to manage security issues relating to Taiwan through the United States, with which it would probably coordinate in case of war.

Still, there are ways that quiet unofficial security cooperation could proceed. One possibility would be to use the Global Cooperation and Training Framework, a platform set up by the United States in 2015 to exploit Taiwanese strengths in addressing issues of global concern. Japan and Australia take part in it. In the past, the platform has covered energy issues but has shied away from overt security themes. Yet there is no institutional reason why it could not address them.

Taiwan and Japan might also think of creative ways to circumvent diplomatic restrictions preventing military contact, such as unannounced cooperation between their coast guards.

Still, all that would be a long way from the full military cooperation with Japan that would maximise Taiwan’s security.