A US Defence Intelligence Agency report in April said several Chinese ground-based laser weapons of varying power were being developed to disrupt, degrade or damage satellites. In a 2007 test, China shot down an ageing Chinese weather satellite from a base in Sichuan province.

While the allies underscored Japan’s plan to pursue a more active “counterstrike capability” and “deterrence” strategy, they did not mention Tokyo’s reported bid to acquire 500 US-made Tomahawk missiles that would put much of China and North Korea within striking distance. If finalised, Japan would become only the second US ally to have the US$2 million missiles after Britain.

To better integrate operations, the allies agreed to a new combined military headquarters akin to the US-South Korea arrangement, with plans for a US Marine Littoral Regiment in Okinawa by 2025.

The regiment – totalling about 2,200 personnel with intelligence, surveillance, logistics units and anti-ship missiles to defend the Japanese archipelago – is seen as both a defensive move and a way to lighten the US military footprint on Okinawa, a major source of social tension.

Japan to expand island military base near Taiwan after China’s missile drills

“I want to reaffirm the United States’ ironclad commitment to defend Japan with the full range of capabilities, including nuclear, and underscore that Article V of the mutual security treaty applies to the Senkaku Islands,” Austin said, adding that he did not see a Chinese invasion of Taiwan as imminent. “There is no challenge that we can’t overcome if we continue to work shoulder to shoulder.”

China on Wednesday criticised the US-Japan defence deal, saying it risked targeting “imaginary enemies” and turning the Asia-Pacific into a geopolitical “wrestling ground”.

“China is a cooperation partner for all countries and poses no challenge to anyone,” said Foreign Ministry spokesman Wang Wenbin in Beijing.

Japan has pledged to double its defence spending to 2 per cent of GDP from 1 per cent within five years starting with a proposed US$51 billion budget this year, up 25 per cent over last year.

“These documents are very significant, in some ways historic. They are showing Japan’s role in the region, its own role in security and what it needs to do,” said Jeffrey Hornung, a political scientist with the Rand Corporation.

“Tokyo and Washington are in the closest alignment they’ve been … The strategic messaging is that we are allies, we are close. And, China, how many allies do you have?”

Wednesday’s 2+2 meetings at the State Department, leading up to Friday’s summit between Biden and Kishida, were also aimed at discussing global leadership issues.

“It’s a pretty amazing moment,” said Sheila Smith, a Council on Foreign Relations fellow and author of Japan Rearmed: The Politics of Military Power. “A lot of people think Japan is pacifist and doesn’t have a military, or they think Japan is a latent militaristic society. The problem with that is, they don’t actually understand the policy.

“This is not something that the US asked Japan to do.”

Japanese public opinion, long bound to its pacifist constitution, has become more wary of China – and to a lesser extent North Korea – as it has felt more threatened.

China-Japan ties: past the point of no return amid Tokyo’s military build-up?

“China and North Korea are their own worst marketers,” said Hornung, a former Defence Department instructor. “They don’t want a strong Japan. But every time they do something, the Taiwan exercises after the Pelosi visit, sailing with Russia in nearby waters, it reminds Japan that China is not getting any friendlier.”

A poll in October by Japanese public broadcaster NHK found that 55 per cent of respondents supported a stronger defence policy – a near doubling over the past decade – compared with 29 per cent opposed.

But analysts stressed that it was one thing for Japan to lay out a blueprint and quite another to roll it out over time.

“It’s a very ambitious agenda,” said Nicholas Szechenyi, deputy Asia director at the Centre for Strategic and International Studies. But Japan also faces likely political battles when the bill comes due and in how to reboot its economy to back its rising security ambition.

“One debate in Japan is resourcing, not only how you’re going to pay for it, but what is Japan’s strategy for sustained economic growth,” he added.

Deploying new missiles, for example, would call on Japan to gain expertise in targeting, damage assessment and rapid coordination with US forces to ensure decisions among allies were coordinated. “All of these things need to be developed,” Szechenyi said.

Itsunori Onodera, a former Japanese defence minister involved in revising the new security blueprints, added that his country could easily get dragged into a war over Taiwan. “Japan has to be aware of this, and do everything we can diplomatically to check China so that conflict does not break out.”

Additional reporting by Orange Wang