Somwhere in the years after the Korean war a bunch of disgrunted Korean officers forms a secret organisation to fully regain the country´s independence.
In 1955, an ultranationalist party is formed, the Korean National-Technocratic Party, from the fusion of smaller nationalist groups and lead by one individual know only as K.N.S. . Contact and cooperation between the technoracy and the military faction begin in 1959.
In the 1960s, the forces of the KNTP gains increasing support. South Korean governement send conscript troops to Vietnam in 64, causing increasingly popular opposition for the "foreign war". The operation have little success and causes the civilian governement to intervene far too much in military matters.
The KNTP grows increasingly popular and win elections in the latter 60s, the south korean governement and the CIA attempts "black op operations" to discredite the KNTP but Noogien is able to expose them, this backfires badly on the South Korean gov.
The south korean governement attempt then to crush the KNTP by force but several generals overthrows it, causing worldwide surprise.
The United States threatens to intervene, to "restablish democrac" by force, hovewer it becomes clear North Korea and China will have none of it and that the Generals may have captured 3 dozens of tactical nuclear US army shells...
In 1972, the militarist regime starts poducting its own nuclear weapons using one French-built nuclear reactor in Seoul, increasingly cooperates with North Korea.
In 1973, the US attempst a counter-coup and US units in South Korea moves against the militarists. Hovewer, the KNTP have organised national militias and its intelligences knew of the operation, in Vietnam the South Korean forces turn on the US with the Viet-Congs and decisively crush the US forces.
In South Korea itself, foreign forces are defeated after a hard battle.
In the 73-75 period, the North Korean military integrates into the southern regime, North Korea itself becomes an autonomous province which economy works at its own pace (Not like IOTL´s ghastly expensive "integration" of east germany).
First satellite is launched and first H bombe is detonated before the end of the 1970s. First mission outside of the atmosphere in the early 1980s, in 1985 the first orbital manned mission is launched as a show of power and skill of the new regime.
In the early 1990s Korea would form an alliance with South Africa soon after the israeli attack on Syria and Jordan. While the Syro-Iranian invaded defeat the overextended Tsahal and began invading the israeli state itself, the Korean governement contacted Saddam Hussein and his exiled governement.
In the 21st centhury, Korea would start the second pacific war and hold its own until the Chinese entry into WW3, while its longstanding allies would cause the Australafrican and 2nd middle-east war but that is another story.