When the government of Republic of China drew the U-shaped line map of the Islands in the South China Sea, the decision-makers may only refer it to the islands within this line. Because ROC held 3 nautical mile of territorial waters, they would not possible to think of including the sea areas of the U-shaped line in the South China Sea. However, with the development of international law of sea, especially the pass of 1982 United Nations Convention on the Law of the Sea, the nature of legal status of the U-shaped Line arise heated discussions. It had been regarded as the islands attribution line, historic waters line, historical rights line or state boundary line. In any rate, this paper tries to use official archives to trace the original thinking of decision-makers and infer its meaning
