Communication of t he U-Shaped Line Map to the United Nations

In May 2009, China sent two diplomatic notes to the UN secretary-general protesting
Vietnam’s submission and Vietnam-Malaysia’s joint submission of their outer continental
shelf claims to the CLCS.50 In these notes, a map of the South China Sea with China’s
U-shaped line is attached as part of the documents. This is the first time that China had
officially used the U-shaped line in defending its claims in the South China Sea. By this
move, China called to the attention of the international community that China’s territorial
and maritime claims were within the U-shaped line. Furthermore, as the U-shaped line map
is attached to China’s objection to outer continental shelf claims, China intended to express
that it would enjoy its rights to the continental shelf within the line.
In response to the Philippines’ diplomatic note dated 5 April 2011,51 China stated in its
Note Verbale that “China’s sovereignty, related rights and jurisdiction in the South China
Sea are supported by abundant historical and legal evidence.”52 China further states that
“[s]ince 1930s, the Chinese Government has given publicity several times the geographical
scope of China’s Nansha Islands and the names of its components. China’s Nansha Islands
is therefore clearly defined.”53 How is China’s Nansha Islands clearly defined? It is through
the use of the U-shaped line.
The 2011 official communication may reinforce the legal effect of the U-shaped line
as it is possible that China has noticed the recent judgments rendered by the International
Court of Justice with regard to the legal force of maps in the resolution of territorial and
maritime disputes. In this regard, the paragraph contained in the 2002 Sovereignty over
Pulau Ligitan and Pulau Sipadan (Indonesia/Malaysia) Case, which has appeared in the
Court’s previous judgments, states that:
maps merely constitute information which varies in accuracy from case to case;
of themselves, and by virtue solely of their existence, they cannot constitute a
territorial title, that is, a document endowed by international law with intrinsic
legal force for the purpose of establishing territorial rights. Of course, in some
cases maps may acquire such legal force, but where this is so the legal force
does not arise solely from their intrinsic merits: it is because such maps fall
into the category of physical expressions of the will of the State or States
concerned. This is the case, for example, when maps are annexed to an official
text of which they form an integral part. Except in this clearly defined case,
maps are only extrinsic evidence of varying reliability or unreliability which
may be used, along with other evidence of a circumstantial kind, to establish
or reconstitute the real facts. (footnote deleted)54
While it is unknown to what extent the map with the U-shaped line would have legal force
in a future settlement of the South China Sea disputes, it is clear that China has attempted
to give it as much legal force as possible. The U-shaped line map now unquestionably
forms an integral part of China’s official documents and, therefore, may “fall into the
category of physical expressions of the will of the State,” thus producing important legal
force.
Raising Questions About the U-Shaped Line
Reduction of Two Segments i n t he Gulf of Tonkin
The U-shaped map originally had eleven segments. But in the late 1950s, two segments
of the line which were located in the Gulf of Tonkin disappeared from the map. Beijing
did not give a public explanation about why the two segments were eliminated from the
map, but this might be related to the transfer of the sovereignty over the Bai Long Wei
Island (Bach Long Vi in Vietnamese) in the Gulf of Tonkin from China to Vietnam.55 It
is said that elimination of the two segments was approved in 1953 by Zhou Enlai, then
primary minister of the People’s Republic of China.56 This change to the map may have
implications. The disappearance of the two segments in the Gulf of Tonkin indicates that
the U-shaped line is flexible with the consequent question that, if China could give up two
segments in the Gulf of Tonkin, why could China not give up the other nine remaining
segments? Since the cancellation of the two segments was relevant to Vietnam’s territorial
and maritime interests, it is not surprising that Vietnam is the most vehement opponent to
the U-shaped line.

Straight Baselines for the Paracel Islands
In May 1996, China publicized part of its baselines along the mainland coast and encircling
the Paracel Islands by the method of straight baselines.57 China used lines connecting
28 basepoints to encircle the Paracels and the surrounding waters. The waters within the
baselines are internal waters and, from the baselines outward, there is a territorial sea of
12 nautical miles. In the same statement, it was declared that China would decide on other
baselines in due time, including baselines for the Spratly Islands.
From these baselines, China may claim an EEZ and/or the continental shelf of the
Paracel Islands. The publication of the Paracel baselines indicates that China did not
consider the U-shaped line to be the maritime boundary line in the South China Sea for
historic waters that were equivalent to internal waters or the territorial sea. Otherwise, the
Paracel baselines would have been unnecessary.58 The baselines within the U-shaped line
have added uncertainty to the interpretation of the legal status of the U-shaped line.

The 2002 Declaration on Conduct in the South China Sea
In November 2002, China, together with 10 member states of the Association of Southeast
Asian Nations (ASEAN), signed the Declaration on the Conduct of Parties in the South
China Sea (DOC),59 which is the first significant regional document specifically applying
to the South China Sea. The DOC expressly acknowledges that China and some ASEAN
countries have territorial and maritime disputes in the South China Sea and that they pledge
to resolve these disputes through peaceful means in accordance with international law,
including the LOS Convention. Since the Declaration is applicable to the entire South
China Sea, it has an impact on the understanding of the U-shaped line. On the other hand,
as a political document, the DOC carries no legal binding force. The existence of the
U-shaped line may be one of the reasons why China has been reluctant to sign a legally
binding code of conduct with the ASEAN countries.