04/10/2026
On August 23, 1971, a bus carrying armed men was heading toward Seoul’s Blue House. A gr***de explosion brought the journey to an end. At first, the military announced that the men were armed communist insurgents. It later corrected the account: they were members of a South Korean special unit who had rebelled on the island of Silmido.
The story began on January 21, 1968, when 31 North Korean agents infiltrated Seoul in an attempt to assassinate President Park Chung-hee. In response, the Central Intelligence Agency established Unit 684 in April of the year. Its 31 members were sent to Silmido and trained for 40 months for a mission to infiltrate North Korea, assassinate Kim Il-sung, and return safely.
Their training was relentless. They practiced shooting, rope climbing, swimming, hand-to-hand combat, bayonet throwing, guerrilla warfare, and survival. Life on the island was isolated. There was no television, radio, newspapers, regular leave, outside visitors, or correspondence. Food and supplies became scarce, while the trainees had no prospect of discharge. Two deployment orders were eventually cancelled as inter-Korean relations changed.
Tension grew. Some trainees deserted, while others were involved in violent incidents. Six trainees ultimately died through su***de or ex*****on. By the summer of 1971, rumors circulated that their requests to be recognized as regular soldiers, discharged, or sent to Vietnam had been rejected. The situation became increasingly explosive.
On the morning of August 23, after a unit dinner the night before, the trainees attacked the soldiers guarding them. Six of the 24 soldiers survived, including Yang Dong-soo, who was shot through the neck but escaped and was rescued that day.
The rebels seized a bus and headed toward the Blue House. They were stopped by military forces in Seoul. Of the 22 trainees who reached the capital, 18 died when after a stand off they detonated hand gr***des. A policeman and five civilians also died.
For years, the Silmido incident remained hidden. Its memory returned to public attention after the 2003 film Silmido, although survivor Yang Dong-soo emphasized that the film contained inaccuracies.