The path to Pyongyang’s latest nuclear test followed a textbook North Korean strategy: escalating provocations accompanied by furious denunciations of annual South Korea-US military exercises. In the 12 days since Washington praised Pyongyang’s “restraint” and held out the prospect of early talks, the North has fired three short-range missiles, sent another one soaring over Japan and detonated what appears to be a full-fledged thermonuclear device. “The hydrogen bomb test was a perfect success,” an announcer on state television claimed after Sunday’s test. The bomb had “unprecedentedly big power” and can be loaded onto a long-range missile, according to the North, a step forward that would dramatically escalate any threat it poses. The blast was its most powerful to date by far and analysts suspect it was from a hydrogen bomb. Japan said it had deployed “sniffer” planes capable of detecting radioactive fallout which can give clues to the type of device detonated, although in the past evidence has been elusive. The North’s state media said no radiation leaked into the atmosphere. While some western media delight in portraying the North Korean government as irrational – or even unbalanced – experts say it shows an extremely refined ability in calibrating and timing its actions to maximise their impact. The fuse for Sunday’s detonation was lit with the test in July of two long-range missiles that appeared to bring much of the US within range. That sparked a fierce warning by President Donald Trump that Washington could rain “fire and fury” on the North, while Pyongyang unveiled a plan to fire a salvo of missiles towards the US territory of Guam. North Korean leader Kim Jong-un later said he was putting the plan on hold, but warned he could still give the order depending on Washington’s next move. The final countdown then began on August 21 when the US and South Korea kicked off an annual military exercise called “Ulchi Freedom Guardian” involving tens of thousands of troops. The North, which sees such war games as rehearsals for invasion, said the US would be “pouring petrol on fire” by going ahead with the drill. Its initial military response came on August 26 with the relatively innocuous launch of three short-range ballistic missiles. That was followed three days later by the far more provocative launch of an intermediate-range missile over Japan – a move that triggered consternation in Tokyo and the wider region. Sunday’s hydrogen bomb test was flagged just hours before by the release in the North’s state media of photos of Kim inspecting a “thermonuclear weapon” capable of being mounted on an ICBM. The North claimed the test marked a “very significant occasion” in achieving the “final goal” of becoming a complete nuclear power. “I think the North has reached a stage where it no longer needs testing. More tests now will be meaningless,” said Koo Kab-woo of the University of North Korean Studies. He pointed to the fact that Pakistan – which has a nuclear programme said to be linked to the North’s – conducted six nuclear tests in total, and may not have seen a need for any further blasts. “If we look at it from Pakistan’s example, the North might be in the final stages” of becoming a nuclear state, he said. The North has given the ultimate demonstration of its power by testing a hydrogen bomb, Cha Du-hyeogn of Asan Institute of Policy Studies said, and wanted the US to believe its claims. “Any technological tests can be seen as playing poker,” Cha said. “You want your opponent to read your move as you intended.” While Pyongyang has tested a missile that apparently brings much of the US mainland into its range, questions remain about its reliability and whether the North has mastered re-entry technology to bring a warhead back through the Earth’s atmosphere. It also has yet to show proof of its claims of miniaturisation. Pyongyang could launch another long-range missile in the next few months, Cha said. In any case, Pyongyang will seek recognition from the international community as a nuclear state, said Go Myong-hyun at the Asan Institute of Policy Studies. If the North’s playbook for the latest test is familiar, there is a wild card in the form of the new occupant of the White House. While his advisers stress diplomacy, Trump has repeatedly raised the option of military measures to shut down the North’s nuclear and missile programmes.