Some animals have developed a defensive tactic, like this fish:
The puffer fish puffs itself up purely for defence. And, that is likely to be the logic behind all the tomfoolery that the DPRK goes on with.
They know from bitter experience, that they will NOT win any war. In the closing phase of the previous Korean war, American saturation bombing almost obliterated any above ground structures, Then came the truce, and the north Koreans attempting to win the best deal, delayed any finality. Since then the ROK (south Korea) and the USA have consistently refused to finalise a Peace Treaty. So what could the DPRK do? Exactly what they have done. They are saying in effect, we know we will lose any future war, but we'll take a lot of people with us. Your victory will come at a very high cost.
I spent a year, at Sydney University studying Korea. The course co-ordinator was Leonid Petrov, who likely knows as much about North Korea as anyone (and, certainly is not an admirer of the regime). If you want to know more about him, he has a FB page and also this reference: https://leonidpetrov.wordpress.com/about-me/
Since then I regularly post about NK on a Macquarie University FB page, so I think by this time I may have also learnt something about NK. I often wonder why, when the Anglosphere has a supposedly free press, why most media commentary on the Korean situation lacks any balance in content, So what is wrong? Why do the N Koreans and their Korean Workers Party feel impelled to act like the pufferfish at the start of this post. Many commentators feel that its because the 'state of war' interrupted in 1953 still exists. The NK elite likely want some sort of assurance that there will be no attempts at regime change.
My opinion is that its worth a try. A former Australian Prime Minister (Bob Hawke), commented during some crisis with the military dictatorship in Myanmar, that the best way to help the people of these rogue states was not via sanctions, because sanctions hurt the ordinary people long before the sanctions hurt the top people. Hawke advocated doing anything possible to build a strong middle class. In the example of Myanmar, Hawke seems to have been right, and I suggest that this is a better course in dealing with North Korea,
China no longer has much influence on the NK government, and if NK uses nuclear weapons on the ROK, a cloud of radiation will drift over the border of China. A wave of refugees will also swamp the dongbei region of China. The river that forms the border is easily crossed in many places. In China, along the border, many Chinese citizens are ethnic Koreans. Many have relatives in NK. They certainly do not want to see a war. And, much of the smaller items of merchandise that are now sold in the small private markets that are transforming the NK economy are smuggled into NK from that part of China.
There is much more to know about the situation. And, the rest of the world also shares some blame. Perhaps Korea would've transformed differently if the rest of the world had intervened to prevent Japan taking over Korea in 1910. But in those days the world was controlled by Imperialists, so Imperial Japan got away with its attempt to make Korea part of Japan. Even the USA acquiesced and made an informal deal with Japan that supported their takeover of Korea and Japan supported the USA's invasion and nasty little war in taking over the Philippines,
So in the closing days of WW2, as Stalin honoured his agreement with Churchill and Roosevelt, a huge Russian invasion force swept across the Japanese state of Manchukuo (that had taken off China) and into Korea and the Northern islands of Japan (the Kuriles and Sakhalin). That's the background to a divided Korea. The Russian army could've easily taken all of Korea, but for some reason Stalin agreed to permitting the US Army to occupy the southern half.
This image purports to show Soviet troops somewhere in Korea
the Captions states:
Soviet soldiers on the march in northern Korea in October of 1945. Japan had ruled the Korean peninsula for 35 years, until the end of World War II. At that time, Allied leaders decided to temporarily occupy the country until elections could be held and a government established. Soviet forces occupied the north, while U.S. forces occupied the south. The planned elections did not take place, as the Soviet Union established a communist state in North Korea, and the U.S. set up a pro-western state in South Korea - each state claiming to be sovereign over the entire peninsula This standoff led to the Korean War in 1950, which ended in 1953 with the signing of an armistice -- but, to this day, the two countries are still technically at war with each other. (Waralbum.ru) #
Reference: http://vfwpost2461.com/1945Photos/Rare%20Photos.htm