Pyongyang’s provocative actions were a sharp reminder of the clear and present dangers facing the country and the JSDF. Add to this an increasingly assertive China, which has tripled its budget in the last decade, cited as a growing danger in the Defence of Japan 2017 White Paper released in August.

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Despite its constitution, Japan has been gradually increasing its defence budget and has the seventh-most powerful military in the world, according to the Global Firepower Index (GFI). This includes 250,000 active personnel, 700 tanks, 2,850 armoured vehicles, 42 destroyers, 17 submarines, four aircraft carriers, 288 fighters, 287 bombers and advanced missile systems. Although North Korea has a standing army of nearly 1 million, more than 5,000 tanks, twice as many combat planes as Japan, and 76 submarines, it has no destroyers or aircraft carriers. North Korea’s less advanced military hardware and a defence budget one-fifth the size of Japan’s leaves it 23rd in the GFI.

However, Prime Minister Shinzo Abe’s recent drop in popularity means he is now unlikely to have the political capital to push through his planned reforms to the pacifist Article 9 of the constitution that would clarify the JSDF’s status and ease the restrictions on its operational capabilities.

The Japanese constitution came into effect in May 1947, imposed by the US occupation forces following the second world war. Its Article 9 states: “The Japanese people forever renounce war as a sovereign right of the nation and the threat or use of force as means of settling international disputes. In order to accomplish the aim of the preceding paragraph, land, sea, and air forces, as well as other war potential, will never be maintained.”

A majority of Japanese constitutional scholars interpret this to mean the JSDF is unconstitutional, but opinions are divided.

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Osamu Nishi, professor emeritus at Komazawa University and a leading constitutional expert, said Article 9 “prohibits aggressive, but not defensive, armed forces”. However, Nishi still believes the article should be revised to remove any ambiguity.

Grant Newsham, a former US Marine colonel and now senior research fellow at the Japan Forum for Strategic Studies, said: “The plain language of Article 9 barely allows Japan to have a police force. By any measure, the JSDF is a military and able to use force and violence if ordered to do so.”

However, Newsham believes the significance of reforming Article 9 would be “as much psychological as anything else; getting rid of that rote belief about Japan not having a military and being somehow immune from danger of the sort a military would address”.

“A North Korean missile smashing into Tokyo will make the fussing over Article 9 irrelevant pretty quickly,” Newsham said.

The JSDF officer, who was not authorised to speak publicly on the issue, said he understood Japan’s armed forces to be technically unconstitutional and saw the lack of changes to the charter since its creation as the major problem.

“Amendments to a constitution to fit changing times are standard globally, but Japan is probably the only country in the world to have not made a single change to its constitution in 70 years,” the officer said. “If the constitution was amended to allow there to be an army to protect the country it would be a natural state of affairs, there is no problem with that.”

Although fiercely criticised by opponents, the limited ‘collective self-defence’ reforms already introduced by the Abe government “are appreciated by the frontline forces”, according to the officer.

“To be able to come to the aid of an ally is normal for armed forces anywhere in the world and allows the JSDF to operate to global standards,” the officer said. “Although critics such as the Liberal Party and Japanese Communist Party said it would increase danger to the JSDF, we don’t see it that way.

“The previous situation was ridiculous: if an ally was being fired upon, we couldn’t fire back until we were directly fired at.”

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The geopolitical shifts in the region and the potential of combat have also brought about a change in mindset within the JSDF.

“In the past there were SDF members who looked at their work like a salaryman would, but that is not the case any more. In particular, the ASDF [air] and MSDF [maritime] are conscious of the dangers,” the officer explained. “Those who can’t accept the new reality have been gradually leaving.”

And US President Donald Trump’s calls for Japan to take more responsibility for its own defence, while unsettling some in Tokyo’s political establishment, have not caused undue consternation in the JSDF ranks.

“We never expected to rely entirely on America. Our basic stance was always that we are there to protect our country. If the Americans came to help, we would be grateful for that, but we have always been conscious that is our responsibility. In that sense, Mr Trump’s statements about Japan having to stand on its own two feet in terms of defence have had a positive impact,” the officer said.

“And we explain properly to our personnel that, contrary to the claims of some opposition politicians, we won’t be going to war for the sake of America.” ■