DMZ - DPRK Tunnels

According to north Korean defectors, Kim Il-Sung -- president of the Democratic People's Republic of Korea -- issued a sweeping order in the early 1970s that required every Korean People's Army division along the Demilitarized Zone to dig and maintain at least two tunnels into South Korea. The opposing United Nations Command had been aware of an earlier north Korean tunneling effort that never became an actuality, but was surprised when new evidence came up that indicated the north was hard at work underground again.

On November 15, 1974 while in operation in the western DMZ near Korangpo, allied reconnaissance troops found steam rising from the earth's surface indicating that a tunnel was present underneath the DMZ. The tunnels depth is believed to be some 45 meters, has a total length of 3,500 meters of which 1,000 meters invaded into the DMZ. The tunnel is along a course that would have exiting soldiers heading towards Korango, Uijongbu and is some 65 km from Seoul, 8 km northeast of Korangpo. It has a prefabricated wall of concrete and slate. When discovered, there were 220-volt and 60-watt lamps, electric lines, railways, and track vehicles. The ground is inclined by 5 degrees to the north to prevent water from gathering. There are turning points on the railroad. The tunnel is large enough to allow the transit of a regiment of troops and heavy artillery every hour.

On March 19, 1975 a second tunnel was discovered following the testimony of Kim Bu-sung, former official of the Liaison Bureau of the Workers' Party of North Korea, who participated in the construction of underground tunnels and defected to the South in 1974. The South Korean Army analyzed the sound of underground explosions which started to be heard in Cholwon in 1972, and examined suspected sites. The arch-shaped tunnel is double the size of the 1st Underground Tunnel. There is a plaza where troops gather, and three exits which were to be used for both conventional and unconventional warfare. The tunnel is located some 13 km north of Cholwon and is 101 km from Seoul. It has a total length of 3,500 meters and is 50-160 meter below the surface. About 3,000 armed troops and their vehicles, artillery and tanks can pass per hour.

On October 17, 1978 a third tunnel was discovered following th e 1975 testimony of defector Kim Bu-sung. Initial efforts to discover the tunnel failed until June 10, 1978, when an excavation hole was exploded, they started to dig a counter-tunnel which later reached the North's tunnel on October 17, 1978. It is about the same size as the 2nd Underground Tunnel, but would have been the most threatening tunnel if the North had used it to invade Seoul. According to Kim Bu-sung, North Korea planned to make five southern exits. Normally one or two were to be used, but in a decisive stage all were to be put into use. It was designed for both conventional warfare and guerrilla infiltration. The tunnel is 4 km south of Panmunjom and 44 km from Seoul. It is 73 meters underground and roughly 1,635 meters long. About 30,000 ranked, heavily-armed troops can pass per hour.

After detecting the sound of underground motors in May of 1989, the Army started excavation work using state-of-the-art reconnaissance devices developed by the Korean Institute for Science and Technology. They sent electric waves through antennas, which were put through excavation halls driven every 20 meters. Analyzing the transformation of the waves, they were able to pinpoint the tunnel's location as well as determine its size. Twenty-three days after they started digging, the counter-tunnel reached the North Korean tunnel. Forty-five Korean and foreign journalists were present at the scene of discovery of the fourth tunnel on March 3, 1990. The tunnel is 145 meters below the surface and is 2,052 meters long. It is located 26 km northeast of Yangku. The tunnel could allow the transit of some 30,000 soldiers per hour.