Japan must "strengthen its defence capabilities", Defence Minister Shinjiro Koizumi has told the BBC, emphasising the need to revisit the pacifist posture that has defined the country since World War Two.

He said boosting defence, "reinforcing its alliance with the United States, and expanding collaboration with like-minded countries" was part of "building multi-layered deterrence critical for ensuring that no new war breaks out in this region".

He spoke of the recent changes in Japan's defence policy, such as relaxing decades-old arms export rules.

For the first time in about 50 years, Tokyo can now sell or transfer defence equipment and lethal weapons to the 17 countries with which it has signed formal agreements, including the US and the UK.

"Australia has selected Japanese war ships. Discussions are under way with the Philippines for used destroyers from Japan's Maritime Self-Defence Force. We are in deep talks with Indonesia, and New Zealand has also showed interest in acquiring Japanese destroyers," Koizumi explained in a sit-down interview at his office in Tokyo.

"This vision of trading equipment and assets throughout the Indo-Pacific is something we have never seen before."

Defence is among the top priorities for the current administration, which has committed to historic spending increases and argues these reforms are needed in what is now an increasingly tense region.

China has emerged as a formidable global player, and North Korea's nuclear ambitions, which have seen it test-fire ballistic missiles over Japan, show no signs of slowing down.

Prime Minister Sanae Takaichi, who came to power in October 2025, has also pushed for revising Article 9 of Japan's constitution, which renounces war as a sovereign right of the nation and the threat or use of force as means of settling international disputes. It also states that land, sea, and air forces, as well as other war potential, will never be maintained.

He said he supported a revision to Article 9 because of how the region has changed over the past eight decades.

"Speaking not as defence minister but as a member of parliament, Japan has not amended its Constitution even once since World War Two. Given how dramatically the security environment has changed, we need to adapt to those changes if Japan is to remain peaceful," Koizumi said.

The southwestern Senkaku islands, which the Chinese call Diaoyu, stretch towards Taiwan and form what's called the First Island Chain. It has been described as a strategic barrier of containment between China's coastal waters and the wider Pacific. But in the past year Chinese aircraft carriers have occasionally operated beyond these islands.

Japan's Defence Ministry identified China's military moves as the "greatest strategic challenge" in its latest white paper report submitted to Cabinet. The ministry is expected to repeat the same in its upcoming annual government report.

Last month, Koizumi rebutted Beijing's claim that his country was engaging in a "new militarism" and argued it was China and its "huge arsenal" of weapons that was of "serious concern" to the international community.

But Japan is keen to keep talking to Beijing, he insisted.

"I met with my China counterpart in November of last year. Because there are areas where our views differ, I conveyed my desire that we continue engaging in dialogue," Koizumi said.

"Unfortunately, there have not been many opportunities for direct communication recently. However, as I stated at the Shangri-La Dialogue, Japan is always open to dialogue. We will continue sending that message and hope that opportunities for dialogue can be created whenever necessary."

Takaichi is not the first Japanese leader to seek these changes. Nobusuke Kishi in the 1950s argued for Japan to have a more normal military posture. Koizumi's father, Junichiro Koizumi, who was PM in the early 2000s, also supported constitutional revision, including reconsidering Article 9.

More recently the late Shinzo Abe, Kishi's grandson, became an advocate of amending the so-called pacifist clause during his time in office.

Koizumi, 45, also told the BBC that Japan needed to clarify the status of the SDF or Self-Defence Forces. Legally and politically, Japan doesn't call it a military - although operationally it functions as one.

"The SDF should be able to carry out its mission with pride and honour, and Japan must possess defence capabilities that remain steadfast even in today's challenging security environment," he added.

Critics have said that formally recognising or expanding the SDF could threaten the pacifist stance of Article 9. Some even argue it doesn't stand in the way of the government's objectives.

"We don't need to amend Article 9 for defensive operations against China. So it's more a political agenda than something based on military rationality," says Hirohito Ogi, a senior research fellow at the Institute of Geoeconomics, studying military strategy and defence policy.

If, for example, there was a threat to the southern islands that Japan controls but Beijing also claims, Ogi believes the current constitution is sufficient. "The attack on US bases located in Okinawa or Kyushu region should be interpreted as a direct military attack on Japan."

While his Liberal Democratic Party is pushing for it, "ultimately, the decision belongs to the Japanese people", Koizumi said.

"Here, constitutional revision is decided through a national referendum. The timing and circumstances under which the public is asked to make that decision involve major political judgements."

But any relationship with China is also a balancing act, especially for a staunch US ally like Japan.

Established after WWII, the US-Japan security alliance remains the cornerstone of Japan's defence. Japan hosts the largest overseas deployment of US forces in the world, with 50,000 or so troops based in the country.

But more recently, US leaders, and President Trump in his second term particularly, have emphasised burden-sharing, suggesting that allies should spend more on their own defence.

"The era of the United States subsidising the defence of wealthy nations is over," Defence Secretary Pete Hegseth said last month during his keynote address at the Shangri-La Dialogue.

Takaichi, known for her hawkish national security stance, has raised defence spending to 2% of GDP, which is double the long-standing post-war benchmark.

Japan plans to invest its increased military budget in new surface-to-ship missiles and unmanned drones deployed on land and underwater.

Some analysts say Japanese industry, such as shipbuilding and electronic systems, could become increasingly competitive in the global defence market.

The emergence of true Japanese defence firms, focused at least primarily on the sector, will be critical to success, according to the Center for Strategic and International Studies.

Others say Japan needs more than larger budgets, updated strategy documents or deterrence, especially against China, and point to bolder reforms to make its forces more nimble and adaptable.

In line with the US view, Koizumi believes Japan should play a key role in maintaining security in the region.

"Japan can make contributions to the region that are uniquely Japanese - not solely through our relationship with the US, but also in our own independent role," he said.

"It's our country. We need to protect it."