The nine-dotted, U-shaped line on Chinese maps encompasses the major features in the South China Sea, including the Dongsha Islands, Xisha Islands, Nansha Islands and Zhongsha Islands. Chinese people first sailed in the waters off the islands more than 2,000 years ago, and discovered and named the islands and exercised effective jurisdiction over them.

Historical evidence shows that the Chinese people discovered the islands in the South China Sea during the Qin (221-206 BC) and Han (206 BC-AD 220) dynasties. Fishing and sailing activities were limited to the waters off the Dongsha and Xisha islands by the Tang Dynasty (AD 618-907) rulers, when China began to send naval forces to patrol and exercise jurisdiction over the area.

By the Song (960-1279) and Yuan (1271-1368) dynasties, Chinese people extended their activities to the waters off the Zhongsha and Nansha islands. The activities covered all the islands during the Ming (1368-1644) and Qing (1644-1911) dynasties, thus establishing China's maritime boundary in the South China Sea.

China has been strengthening efforts to protect its sovereignty in the South China Sea since the early 20th century. The Kuomintang government examined and approved of both the Chinese and English names for all the Chinese islands and reefs in the South China Sea in December 1934 and grouped them into four archipelagos for the first time.

A map published in April 1935 shows the Chinese islands in the South China Sea in details, marking the southernmost tip of the South China Sea as Zengmu'ansha at 4-degree latitude north.

Another map, published in February 1948, shows the administrative division of the Republic of China. The map also shows 11 dotted lines encircling the four archipelagos with its southernmost point at Zengmu'ansha. It was the first map to mark the U-shaped maritime boundary of China in the South China Sea.

Maps published after the founding of the People's Republic of China retained the 11-dotted line, and it was not until 1953 that the two dots marking the Beibu Gulf were deleted. After that, all Chinese maps have followed the nine-dotted, U-shaped pattern.

The U-shaped line is the result of a long historical process that has established China's sovereignty over the islands in the South China Sea and their surrounding waters. In October 1947, the materials presented by the then home affairs ministry to the Kuomintang government shows China's sovereignty claim over the islands and waters within the U-shaped line.

In contrast, Vietnam, Malaysia and the Philippines hardly knew anything about the islands in the South China Sea before China's Qing Dynasty (1644-1911), nor did they have any evidence to prove their forefathers' activities in the South China Sea, let alone naming any of the islands.

China's maritime boundary in the South China Sea is the result of historical evolvement, and it is the only country to develop the region continuously throughout history, and, hence, the Chinese people have the primal right over the islands in the South China Sea.

According to Chinese legal expert Zhao Haili, China owns the historic title over the islands, reefs and shoals within the nine-dotted line, although that does not mean the entire sea within the line is part of China's internal waters.

Although the 1982 United Nations Convention on the Laws of the Sea (UNCLOS) does not specifically talk about historic title, Article 15 of the convention says: "The above provision does not apply, however, where it is necessary by reason of historic title or other special circumstances to delimit the territorial seas of the two States in a way which is at variance therewith."

Chinese people have fished and sailed in the South China Sea for more than 2,000 years, and China established its historic title long before the UNCLOS came into effect. China's historic title over the islands in the South China Sea conforms to UNCLOS and international laws and, therefore, should be respected.

When China first announced the U-shaped line in the South China Sea, the international community did not oppose it nor did any of the adjacent countries protest against it. Instead, the nine-dotted line was part of the maps they published, reflecting their acceptance of China's sovereignty over the islands in the South China Sea.

In recent years, however, several Southeast Asian nations have questioned the legitimacy of the nine-dotted line, but their claims cannot be justified.

After the adoption of UNCLOS, it is indeed important to appropriately and scientifically interpret the U-shaped line. But the U-shaped line took shape long before UNCLOS came into effect, and using it to decide whether the long-established line is reasonable or deny its legitimacy actually deprecates history.

All signatory countries to UNCLOS should understand that the convention is just one of the international laws of the sea, not the only one, and thus should stop questioning the legitimacy of China's nine-dotted line.

The author is a research scholar with the Research Center for Chinese Borderland History and Geography, Chinese Academy of Social Sciences.

(China Daily 07/22/2011 page9)