Date of Award


Document Type


Degree Name

Master of Laws (LLM)


Regardless of its uncertain legal status, it is the legal reality that the Northern Limit Line (“NLL”) has served as a de facto maritime demarcation line in the Yellow/West Sea in the absence of a peace treaty for the Korean Peninsula. Aside from its legal definition, however, the core of the NLL conflict is whether it has been historically consolidated as a valid legal system that may be enforceable against all States, and whether South Korea has historic title over the waters lying south of the NLL. In order to find an answer, it is important to determine whether there was either recognition or acquiescence on North Korea’s part during the formative period.

Judging from international legal practices and jurisprudence, has South Korea’s claim of historic title consolidated? The answer is yes for the following reasons. First, South Korea has continually exercised its sovereign authorities before and after North Korea’s first-ever has continually exercised its sovereign authorities before and after North Korea’s first-ever protest in 1973, though the absence of relevant domestic legislation is still pointed out.

Secondly, South Korea sufficiently manifested its sovereignty around the vicinity for two decades. Given the particular circumstances of the Peninsula, the two-decade period seems legally sufficient for the purpose of historical consolidation. Given the fact that North and South Korea had debated over the maritime delimitation in the course of the armistice negotiations, both must have been highly sensitive to this issue as belligerents and must have recognized its importance. Most significantly, as multiple historic instances indicate, North Korea had acted in recognition of the NLL after the establishment of the armistice system.

Third, South Korea fulfilled the requirements of effective occupation for the period considering North Korea’s effective acquiescence. Therefore, North Korea’s late protest violates the principle of estoppel. North Korea should have launched a protest during the time when South Korea formed its historic title through the public and notorious exercise of its governmental authorities. North Korea must have taken advantage of the stability provided by the NLL’s role as a de facto maritime demarcation line while rebuilding its naval force. For international stability, therefore, North Korea must be estopped from protesting at a later time as against South Korea’s reliance on North Korea’s silence.