There's a good chance that a process of change is occurring in NK, which I'll come back to, as first I'd like to briefly explain how Korea became divided.
I've spent a lot of time this past calendar year on the history and development of Korea, this last semester focussing on modern Korea with all its sadness, commencing with the Japanese takeover in 1905, and the full annexation and military occupation in 1910.
Many Korean's (naturally) opposed the Japanese occupation. Some actively fought the Japanese as guerilla's in the mountains. Kim Il-song's family, who were Christians were among the opposers, so we can assume that anti-japanese talk was part of the families conversation. When Kim Il-sung turned 14 he left school and attempted the establishment of a patriotic youth group with leftist tendencies. When the Japanese eventually caught him he was jailed for 17 months. On release he took to the hills and joined an anti-japanese guerilla group in Manchuria. This brought him into contact with the Chinese Communist Party that by this time was organising the Chinese anti-japanese war in the North of China from their HQ in Yenan in N.W. China. (Officially, the Japanese had taken over Manchurua also and set up an independent government and appointed the former Chinese Emperor, Pu Yi as head of state.)
The Japanese Kwantung Army which was very powerful, both politically and as a military force, gradually made life very difficult for the guerillas and eventually forced these groups, including Kim Il-sung's, out of Manchuria into Russsian Siberia. Here for the first time, Kim came face to face with the power of an industrialised socialist state. The Russians (never sure if Japan would attack) maintained a very strong army on its borders with Japanese forces. That Army fought two actions against the Japanese prior to WW2 and won both of them, quite interesting to know that when considering the ease with which the Japanese over-run the Philipines and S.E.Asia.
As WW2 progressed and the tide turned in favour of the western Alliance, Churchill and Roosevelt pressed Stalin to declare war on the Japanese, which Stalin agreed to do, after the defeat of Germany. After Germany's surrender Stalin assembled a huge Army on the borders of Manchurua. Over 1,000,000 soldiers, 20,000 field guns, 5000 tanks, and 5000 aircraft. All this was done under cover of darkness and when Russia finally declared war on August 8, 1945, striking in three large pincer movements the Japanese crumbled. In just 6 days the Soviet armies overrun an area the size of Europe, including penetration of the Korean Peninsula. The American administration had hardly given any consideration to the future of Korea. An emergency meeting of Army Generals decided a partitioned arrangement may be agreed to by the Russians, which is what happened and which act was the real commencement of the current situation of two Koreas.
Kim Il-sung and his band of guerilla's had been inducted into the Soviet Army and he was brought back as part of the Soviet adminstration, along with other Koreans who had been fighting against the Japanese with the Chinese Communists in Manchuria. In reality many Koreans stayed on in China to fight against Chiang Kai-shek's Nationalist Army - the beginning of a debt of blood that eventually forced the Chinese government of the new Peoples Republic of China into the Korean war (among some other reasons).
From the end of WW2 until the beginning of the Korean war, Koreans migrated to the side with which they felt most affinity, leftist sympathisers went north and rightists went south.
Out of that came the current situation and a major tension point in world affairs.
So is the tension between north and south going to wane ? - Too early to say that, but many observers who travel to North Korea (which may not be what many in the west imagine) are noting signs of change.
In particular, our lecturer for the last few months, sent this web reference out today:
Its published by Cankor, a Canadian organisation that claims to seek a rational solution to the NK/SK divide. The author is Ruediger Frank who was in North Korea in April and has just returned from a second visit.
find his story at: vtncankor.wordpress.com/2012/10/19/an-atmosphere-of-departure-and-two-speeds-korean-style-where-is-north-korea-heading-by-ruediger-frank/