Northern Limit Line - Origins

Origins

The 1953 Armistice Agreement which was signed by both North Korea and the United Nations Command (UNC), ended the Korean War and specified that the five islands including Yeonpyeong Island, Baengnyeong Island would remain under UNC and South Korean control. However, they did not agree on a maritime demarcation line, primarily because the UNC wanted to base it on 3 nautical miles (5.6 km) of territorial waters, while North Korea wanted to use 12 nautical miles (22 km).

After the United Nations Command and North Korea failed to reach an agreement, it is widely believed that the line was set by the UNC as a practical operational control measure a month after the armistice was signed, on August 30, 1953. However original documentation recording this has not been found. The line was originally drawn to prevent South Korean incursions into the north that threatened the armistice. However, its role has since been transformed to prevent North Korean ships heading south.

A 1974 Central Intelligence Agency (CIA) research report investigating the origins of the NLL and its significance, declassified in 2000, found that the NLL was established in a 14 January 1965 order from the U.S. Commander Naval Forces, Korea. An antecedent line, under a different name, had been established in 1961 by the same commander. No documentation about the line earlier than 1960 could be located by the CIA, casting doubt on the belief that the NLL was created immediately after the armistice. The sole purpose of the NLL in this original order was to forbid UNC vessels from sailing north of it without special permission. The report noted, however, that in at least two places the NLL crosses into waters presumed to be under uncontested North Korean sovereignty. No evidence was found that North Korea had recognised the NLL.

While the NLL was drawn up at a time when a territorial waters limit of 3 nautical miles (5.6 km) was the norm, by the 1970s a limit of 12 nautical miles (22 km) had became internationally accepted, and the enforcement of the NLL prevented North Korea, in areas, from accessing significant territorial waters (arguably actual or prospective). In 1973, North Korea began disputing the NLL. Later, after the 1982 United Nations Convention on the Law of the Sea, the NLL also prevented North Korea from establishing an effective Exclusive Economic Zone to control fishing in the area.

It is unclear when North Korea was informed of the existence of the NLL. Many sources suggest this was done promptly, but in 1973 Deputy Secretary of State Kenneth Rush stated, in a now declassified, "Joint State-Defense Message" to the U.S. Embassy in Seoul that "We are aware of no evidence that NLL has ever been officially presented to North Korea." However, South Korea argues that until the 1970s North Korea tacitly recognized the line as a sea demarcation line. North Korea recorded in their 1959 Central Almanac a partial demarcation line close to the UNC controlled islands, at about three nautical miles distance, which South Korea argues shows North Korean acceptance of the NLL as a whole.