The Great Leader’s Shadow War
In the late 1960s, North Korean president Kim Il-sung sent commandos to infiltrate South Korea
In the fall of 1966, things really began to change on the Korean Peninsula.
The armistice agreement that had marked the de facto end of the Korean War in 1953 had created a demilitarized zone between North and South Korea, a buffer area intended to keep the two countries at a remove.
It didn’t always work. In the years since the ceasefire, the DMZ would be home to occasional clashes which served as brief reminders that the two countries were technically still at war. In 1965, North Korean forces killed 20 South Korean soldiers and four in the year before that. 
But starting in mid-October, the atmosphere along the DMZ took a dark turn, foreshadowing a bloody end to the decade. North Koreans, often intelligence agents looking to cross the border through the DMZ, had generally avoided U.S. and South Korean patrols so they could slip through unnoticed.
Now, North Korean forces were heavily armed and actively seeking them out. In a five-day period starting on Oct. 13, 1966, North Korean troops carried out five ambush attacks against soldiers from the Republic of Korea. 
U.S. president Lyndon Johnson was scheduled to visit South Korea in a few weeks, but the CIA dismissed the idea that the violence was related. A Presidential Daily Brief offered instead that Pyongyang might be looking to test the mettle of a handful of units that Seoul had recently deployed to the DMZ. 
Then on Nov. 2, just as Johnson was about to end his trip to South Korea, a North Korean ambush killed six American troops and one South Korean soldier. 
The incidents marked the opening salvos in a campaign of subversion and guerrilla warfare that plunged the Korean Peninsula into violence throughout the late 1960s. Kim Il-sung, founder of the Stalinist dynasty that has ruled North Korea since 1948, had decided to send hundreds of commandos and intelligence operatives to the South to recruit disaffected citizens, carry out acts of sabotage, attack U.S. and ROK troops and build the covert infrastructure to foment a communist revolution.
Read the Remainder at War is Boring