North Korea has conducted its sixth nuclear device test, and based on what we know so far it looks like by far the biggest yet. Pyongyang's own news agency, KCNA, described the test as a "perfect success", and claimed the device was an advanced hydrogen bomb small enough to fit atop a long-range missile.

Though it's still too soon to confirm whether that's true, whatever the north tested was clearly much larger than its previous devices. Seismic readings detected the blast via a 6.3 magnitude earthquake, and Norway's NORSAR seismological observatory suggested the explosive yield would translate to a massive 120 kilotons.

After an extremely tense few months of tough rhetoric, missile launches, military exercises and troop movements, it seems North Korea has come very close to achieving what it's always said it was after: a viable missile-borne thermonuclear deterrent. So has the time finally come to run for the bomb shelters?

Before answering that, it pays to take stock of what the north has been up to of late – and why.

The best-laid plans

As of September 4, North Korea had tested more than 20 missiles in 2017. Some were short-range, some medium-range; many of them were targeted to land into the East China Sea. Some launches failed, but one flew over northern Japan. None of these launches took place in a vacuum. They are part of a delicate, almost choreographed interplay between East Asia's most important actors, a dance of military moves, domestic political shuffling and international aspirations.

The Korean peninsula's problems always come down to the unresolved issues of Korean partition, the post-Korean War armistice, and the thousands of US troops permanently stationed in the region for the sake of Japan and South Korea's reconstruction and protection. The American military presence is a direct threat to the security of the Pygonyang power elite, and provides a pretext for the Kim government to claim it needs a massive military and a nuclear deterrent.

In the last year, the north has been especially concerned with the US's deployment of the the Terminal High Altitude Area Defence (THAAD) system, a Lockheed Martin-manufactured ballistic missile interceptor. THAAD is controversial in China and South Korea too, but it had arrived on the peninsula by March. By then, North Korea had already tested a new Pukguksong-2 missile, apparently assassinated Kim Jong Un's stepbrother, Kim Jong-nam, and launched four intermediate-range ballistic missiles into the East China Sea on March 6.

With THAAD partially deployed and operational by early May, and with a new South Korean president assuming office, North Korea fired off various other missiles of other ranges in the ensuing weeks. The US, meanwhile, conducted its usual joint missile drills with South Korea and dispatched military ships to waters near the Korean peninsula.

The international community also condemned, as is customary, all of the launches with the standard volley of castigations: unacceptable, deplorable, beyond the pale. It all culminated on August 5 with United Nations Security Council Resolution 2371, which further targets North Korean exports and imports and its foreign workers.

Clearly that resolution hasn't deterred the north from its plans. But though this test looks like a giant step, technologically and politically speaking, it's only a small one.

Business as usual?
While the world's attention was mostly focused on the diplomatic tit-for-tat – and especially with what Donald Trump would do when forced to take an actual decision on North Korea – a number of sources, including the site 38 North, were already reporting that the established Punggye-ri test site was prime and ready for a new nuclear test, and had been as early as April. That in itself was hardly surprising; a bigger, more mobile bomb is just latest step in the nuclear programme, and has always been on the agenda.

Yet Pyongyang still hasn't made it all the way.

Even if it might (and only might) be able to fit a hydrogen bomb onto a missile, it still has to solve other stubborn technical problems, particularly how to design long-range missiles that can re-enter the atmosphere without burning up.

Meanwhile, in the absence of ill-advised and highly unpredictable military action, the international community seems to have little up its sleeve other than sanctions and tough rhetoric. So far, both have failed – and they could be starting to backfire.

When Donald Trump threatened the north with "fire and fury" in retaliation for its long-range missile tests, I suggested it was likely that his inflammatory rhetoric would only spur Pyongyang to test yet more missiles. It seems this will continue. As soon as he woke up to the news of the latest nuclear test, Trump not only suggested that North Korea was a rogue nation, unsurprising, but that it was an embarrassment to China.

This is a fundamental misunderstanding. Yes, Chinese trade is vital to the North Korean economy, but Pyongyang is responsible for its own behaviour. This crisis draws its energy not from China's supposed enabling, but from the way North Korea understands its own security and protection – and as mentioned above, that worldview dates all the way back to the Korean armistice and its unresolved problems.

As things stand, it's clear that the north has developed enough technology to claim the title of "nuclear power", and whether or not other nations think it has the right to be regarded as such is irrelevant. Equally, any military incursion on northern territory would very likely meet with retaliation from what's now a nuclear-armed state, meaning any discussion of conventional military intervention is effectively moot.

The Conversation All the parties involved are fully aware of this. And as such the only way forward in this crisis is through some sort of dialogue about how to control the north's nuclear arsenal. When the safety of millions is at stake, talking with an opponent is no sign of weakness.