But this time it was actually scary. The hermit nation had, it claimed, successfully tested a hydrogen bomb. Kim reportedly declared this alleged feat an "H-bomb of justice."
Kim has provoked the West and his neighbors numerous times but what could he want now and why?
, 32, is the youngest son of former North Korean leader Kim Jong II. In December 2007, the elder Kim received a personal letter from then-President George W. Bush asking that the country dismantle its nuclear weapons program after North Korea pledged during talks in Geneva to do so. There's a long history of the West using diplomacy and sanctions to try to keep North Korea in check regarding nuclear weapons, according to the Arms Control Association
, a respected Washington-based think tank that focuses on proliferation. In short, these efforts, over the long run, have not succeeded in convincing the secretive nation to reduce its nuclear ambitions.
Kim Jong Un took over when his father died in December 2011. And he's been a standout in both his viciousness --he's had 70 officials executed since taking control
-- and his commitment to appear tough to the rest of the world.
Sue Mi Terry, who worked as a CIA analyst focused on North Korea, said Wednesday that she wasn't surprised at all about an announcement that North Korea had tested a nuclear weapon. But she was surprised they claimed it was a hydrogen bomb.
"North Korea has always wanted to be seen as a nuclear power like Pakistan," she said.
"If it's true about the hydrogen claims, the intelligence community are very wrong about North Korea," Terry said. "And I'm coming from that background: North Korea is one of the hardest countries to figure out. There's so much that we don't know. We can't just say that it could never happen."
Does he want something like the Iran deal?
One possibility is that the Iran nuclear deal might have influenced Kim, said Terry.
"The Iran nuclear deal, they might think, means that Iran is getting a couple million in payoffs. It's the whole 'provoke and get paid' cycle."
The recent United States nuclear negotiation with Iran -- in which Iran stands to make significant financial gains -- might have led Kim to believe that North Korea could negotiate a similar deal with financial gains for North Korea.
What about past disarmament negotiations?
The West has been trying to contain Kim and his father before him for decades. But let's jump to this year. In February, the U.S. and North Korea met in Beijing, China, and the two countries agreed that North Korea would suspend operations at a uranium enrichment plant, Arms Control said.
North Korea invited International Atomic Enrichment Agency inspectors to monitor their activity and vowed to set moratoriums on nuclear and long-range missile tests, according to Arms Control. The initiative fell apart over the ensuing months, followed by years of unpredictable talk and behavior, during which North Korea has tested missiles repeatedly, provoking neighbors such as South Korea and the West.
Mike Chinoy, a North Korea expert, said that the latest outrageous -- if more serious -- threat is just one of many over the years from Kim. Chinoy wrote "Meltdown: The Inside Story of the North Korean Nuclear Crisis" and is a scholar at the U.S.-China Institute.
He surmised that Kim doesn't want to talk from a position of weakness, especially given that the United States has said the only basis for negotiations would be for North Korea to shed entirely its nuclear weapons program.
Is he trying to seem like a big shot at home?
Kim is less motivated by what his hydrogen bomb claim can cause internationally than he is concerned about what it can do for him domestically, some experts believe. He wants and needs to project an image as a powerful leader. He's concerned about legacy, they say.
Gordon Chang, a Forbes columnist and the author of "Nuclear Showdown: North Korea Takes On the World"
said on CNN Wednesday that Kim is fostering "good regime politics."
"It helps him with other people in [North Korean capital] Pyongyang," Chang said.
Balbina Hwang, a former U.S. State Department adviser during the second Bush administration, said Wednesday that North Korea's leader is "primarily driven by domestic reasons."
"Since its founding in 1948," she said, the North Korean regime "has essentially felt insecure and is obsessed with regime survival."
Why would regime survival be so critical to Kim?
The answer, in short, is that there are no obvious successors, said Terry. Leadership legitimacy in North Korea, she said, is based on bloodline.
In 2013, Kim's uncle was executed
for trying to overthrow the government, the Korean Central News Agency reported. Earlier this year South Korea claimed that Kim had executed 70 officials
since he took his father's spot leading the nation.
Kim has a brother who was, at least for a time, reportedly living in Macau, but Terry said, he is seen as a highly unlikely successor, not least because he is thought to be quite Western minded.
"There might be some military guy who steps forward," she said, "but other than that, there's no clear successor."
Kim's move to declare that a successful hydrogen bomb test occurred is a way demonstrate that he can survive no matter what, she said.
What's China got to do with it?
United Nations measures imposed over the years haven't prevented North Korea from advancing, said Victor Cha, the director of Asian Studies at Georgetown University. He called China the "weak link" in global efforts to stem North Korean aggression.
China is "by far the biggest supplier of commercial" goods to North Korea, he said, and so far, "they are not willing to step on the neck" of North Korea to get the nation to change.
Cha said China is more concerned about the leader they don't know. In other words, the Chinese prefer the relative stability of the current regime to the chaos that could follow some kind of regime change in a country right on their border -- refugees could be a huge problem, for example.
For that reason, Terry believes that even if it's proved that North Korea launched a successful hydrogen bomb test, China might stick with its approach.