1. International law on maritime boundary

The space where men live on earth is composed mainly of three parts: the land, the sea and the sky.

The land - including land, islands, rivers and streams, inland lakes, and the under ground beneath - has long been divided out among countries and represented by the national borders defined by managerial actualities or by treaties. The land border is considered subtainable and inalienable. However, the fact is that today a lot of disputes over borders still take place and the borders on land among the nations of the world are not always stable. It can be confirmed that any new outcrop (island), which appears on the sea, will be occupied by this or that person immediately.


Basically, the airspaces of nations have been also clearly defined long time ago, and mainly based on the division of land.

As for the sea areas, there have been new major changes recently in respect of the scope and legal status of sea waters belonging to a coastal nation, as well as the sea waters, seabed and sea subsoil without belonging to any country. The fundamental principle of the law on the sea is possessting the land first and after that the sea. These changes can be seen taking place along the process of three basic steps as follows:

- From the ancient time until the mid-20th century, the coastal states only had narrow territorial waters (territorial waters) under their sovereignty of three nautical miles wide (a nautical mile = 1,852 m). All the outer remainder was the common sea. Individuals, organizations, vessels of each nation should enjoy the right to freedom of the seas. Virtually, the sea was not divided among any one, the borders on the sea in the territorial waters of the nations were usually formed and respected in accordance with practices and customs.

- From 1958 to 1994, the coastal nations had narrow territorial waters and contiguous areas, not exceeding 12 nautical miles wide, the continental shelves extending under the sea in less than 200 m of the depth of the water (under the 1958 UN Convention on the Law of the Sea). Nations adjacent to opposite to each other, based on their national laws, defined the sea waters by themselves, which possibly led to overlapping. The then international maritime law stipulated that nations having overlapping areas ought to work together to define the maritime boundaries (including the boundary in territorial waters, boundary in contiguous areas and boundary on continental shelves) in overlapping areas.
                                    
The principle for delimiting the common boundary in the territorial waters is based on agreement between the nations concerned; if not, it would naturally follow the median line (the line equidistant from the nearest points of the territorial sea baselines of each of the two nations) unless there are reasons of historical title or other special circumstances (Article 12 of the Convention on the Territorial Sea and adjacent areas in 1958).

And the principle for demarcating the boundary in the continental shelves is that nations adjacent to or opposite to each other ought to do it together in order to come to an agreement. If a mutual agreement could not be reached, the equidistant line would be naturally used as the boundary line (Article 6 of the UN Convention on the continental shelf in 1958).

Thus, in this period, the principle of maritime boundary demarcation was mainly based on agreements among the nations concerned, otherwise, the median line would be applied.
However, the mechanical use of the median line could lead to unreasonability owing to the fact that the geographic conditions of sea waters are largely varied. Therefore, later, in the 1982 Convention, the median line was no longer used as a principle.

From 1994 to present: The new UN Convention on the Law of the Sea was signed by nations in 1982, but not until 16 November 1994, did it take the international legal effect. The Convention was ratified by Vietnam in 1994. Under this Convention, a coastal state has five sea zones: Internal water, territorial sea area (12 nautical miles wide), contiguous zone (12 nautical miles wide), the exclusive economic zone (200 nautical miles wide ), the continental shelf (from 200 nautical miles up to maximum 350 nautical miles wide). With the advent of the 1982 Convention, the nations worldwide would have to demarcate about 412 new maritime boundaries. Before 1994, a number of countries had demarcated the sea boundaries among themselves in the spirit of the 1982 Convention.

When the aforesaid zones of the nations adjacent to or opposite to each other are overlapped, the parties concerned must carry out demarcation of common boundaries in these zones together. The principle for demarcating boundaries in the territorial seas remains as before, namely the nations must reach mutual agreements, if not, the median line shall be applied by the parties concerned (Article 15, the 1982 Convention).

The principle for demarcating boundary in the exclusive economic zone and continental shelf is similar, namely, nations that are adjacent to or opposite to each other must discuss with one another on the basis of international law so as to be able to reach an agreement to a solution equal to all parties. If not, an international judiciary agency (International Court of Justice) could be resorted to. While waiting for settlement, the parties may agree to provisional solutions for mutual exploitation and use of the relevant waters without jeopardizing the border demarcation. Where agreement or treaty on the division has been reached among the nations concerned, the validity of that agreement or treaty is retained. (Articles 74 and 83, the 1982 Convention).

The fundaental in accordance with the 1982 Convention is mutual agreement and fairness in conformity with international law. The Convention does not require any specific dividing measure to take and it is up to the nations concerned to have their consideration. However, through practices, it is usually started with the median line, then appropriate adjustments will be made to achieve justice for the nations concerned.

2.  Factors related to maritime boundary demarcation

In applying the provisions of the 1982 Convention for demarcating maritime boundary, there are a number of factors involved. First, a coastal nation shall work out regulations and demarcate the boundary on its sea areas in accordance with the provisions of the 1982 Convention.

Second, however, the boundary in the overlapping sea areas must be the line which is mutually discussed about and agreed upon, or mutually accepted by the nations concerned if the settlement is made by the International Court of Justice. The boundary in overlapping waters, which is unilaterally set, shall only be deemed a claim only, there is no international legality implied.

First, the parties must jointly specify the overlapping areas to be addressed. Then, to ensure the principle of equality, they should consider the special circumstances involved, mainly the natural geographical conditions, such as the relevant coastline morphology (convex or concave coast), the length of the general direction of the coastline of the parties, and the presence of islands in the relevant sea area. The islands, depending on location, size, and agreement between the nations concerned, will be given different effects in delimitation.

From the legal point of view, economic factors such as resources, traditional marine exploitation and use, maritime traffic need... are not the factors directly related to boundary delimitation. However, when addressing it, in order ensure reasonableness and fairness in conformity with regulations on allowing catches of excussive marine resources in the exclusive economic zones and on encouraging the concerned nations to cooperate in protection of natural resources and sea waters, taking into account the legitimate interests of the people living in the relevant waters, maintaining peace and stability on the sea, the nations concerned often consider these factors in their discussions for a settlement.

There are a number of nations concerned who, owing to the complexity of the issue, cannot resolve the boundary demarcation on the sea by themselves, may have recourse to the International Court of Justice for a settlement. However, the majority of nations wish to find a solution through peaceful negotiations. Solutions jointly sought by the nations concerned themselves are usually more reasonable, equitable and sustainable, easier to put into practice.

3. Vietnam’s viewpoints and policies on maritime boundary delimitation with the relevant nations

Vietnam is a country with a long coastline, wide sea areas, islands and archipelagoes, especially the two archipelagoes of Hoang Sa and Truong Sa lying in the middle of the East Sea. In the past, in accordance with the 1958 Convention on the Law of the Sea, Vietnam would have territorial sea boundaries with China and Cambodia; boundaries on the continental shelves with China in the Tonkin Gulf, as well as with Indonesia, Malaysia, Thailand and Cambodia. Now, under the 1982 Convention, Vietnam has boundaries in the exclusive economic zones with some relevant nations. In addition, Vietnam’s outer limits of the exclusive economic zone and continental shelf are extended much further in the East Sea. Therefore, it can be said that in conformity with international law, Vietnam will have to negotiate to settle maritime boundary issues with seven countries, namely China, the Philippines, Malaysia, Brunei, Indonesia, Thailand and Cambodia.

On 12th May 1977, the Vietnamese Government issued a Declaration on the territorial sea, contiguous zone, the exclusive economic zone and continental shelf of Vietnam. Article 7 of the Declaration stipulates that: "The Government of the Socialist Republic of Vietnam will, together with the countries concerned, through negotiations on the basis of mutual respect of each other’s national independence, sovereignty in conformity with international law and practice, settle differences relating to sea areas and continental shelves."

The Resolution of the Vietnam National Assembly on 23th June 1994 on the ratification of the 1982 UN Convention on the Law of the Sea affirmed Vietnam’s sea waters as declared by the Government in 1977 and in conformity with the provisions of the 1982 Convention, while stating "... advocate addressing the disputes over territorial claims and disputes relating to the East Sea through peaceful negotiations in the spirit of equality, mutual understanding and respect, respect for international law, particularly the UN Convention on the Law of the Sea in 1982..."

So, the fundamental viewpoint of our State on delimitation of the maritime boundary in the overlapping areas with the neighboring countries is through peaceful and equitable negotiations based on international law to find solutions, fair to the parties concerned.

Based on the policies of the Party and State, Vietnam has been implementing the maritime boundary delimitation with the relevant neighboring countries.

4. The situation and practical settlement of the demarcation of maritime boundary between Vietnam and a number of relevant neighboring nations

Thailand

In 1971, Vietnam stipulated its continental shelf in southern Vietnam, including the sea area between Vietnam and Thailand, where the border line goes along the median line between the baselines of Vietnam’s island (Tho Chu) and the coastline of Thailand. In 1973, Thailand regulated its continental shelf boundary along the median line between the coastline of Thailand and Vietnam’s Phu Quoc Island. An overlapping area of about 6,000 km2 was formed between the two parties.

The overlapping sea area between the two nations is situated in the Gulf of Thailand, home to many natural resources, including seafood, oil and gas.

The two parties conducted negotiations from 1992 to 1997. During the negotiations, both parties based on international law and specific natural conditions of relevant sea area, including the length of the general coastline direction, effects of the islands, median line delimitation method, taking into account the interests of the other nations concerned... Having made careful consideration, the two parties found that owing to its location which is far from the coastline, about 87 nautical miles (161 km), and in conformity with  international law and practice, Tho Chu Island could only be given one third effect of the delimitation.

In August 1997, the Governments of the both countries signed an agreement to delimit the boundary in the exclusive economic zones and continental shelves between the two countries in a straight line of about 74 nautical miles (137 km) long.

This is the first maritime boundary agreement signed between Vietnam and one of the neighboring nations. After the signing, maritime management and fisheries activities were put into order and discipline, the situation on the sea became stable, the oil and gas exploration and exploitation on the two sides of the border line were very active and of positive outcomes. Vietnam’s oil companies have announced commercial discovery of four large gas fields on its continental shelf in the Gulf of Thailand.

Malaysia

At the estuary of the Gulf of Thailand, Vietnam and Malaysia have a small overlapping area covering about 2,800 km2. The outer limit of the continental shelf of Vietnam in the area was defined in 1971. Malaysia introduced its boundary in 1979.

In the overlapping area between the two countries, three oil and gas fields of commercial production were discovered. In 1992, negotiations between the two countries were started. In the negotiations, both parties realized that if they discussed on delimitation in the  overlapping area, it would take time and an early exploitation of oil and gas fields for the socio-economic development of each country could not be carried out; the overlapping area was not so large, which could be cooperated for joint management.

Therefore, based on the provisions on provisional arrangement pending the settlement of border issues, both parties agreed to sign the agreement on "joint exploitation" of the overlapping area in 1992 on an equal basis in all aspects: investment, profit sharing and management without hampering the delimitation at a later stage. Both parties assigned Vietnam Oil and Gas Corporation (PetroVietnam) and Malaysia’s Petroleum Corporation National Berhad (Petronas) to sign and implement, on behalf of their governments, a joint commercial agreement on exploitation, and formed a joint coordination committee.

This is Vietnam’s first agreement on joint exploitation with a neighboring country.

The oil fields in the overlapping area between Vietnam and Malaysia are our third field, which commercially produces oil and gas, enhancing our export capability, bringing about a large source of foreign currency for the cause of economic construction, and contributing to the development of cooperation and friendship between Vietnam and Malaysia.

China

On 25th December 2000, Vietnam and China signed the agreement on demarcation in the territorial waters, exclusive economic zones and continental shelves in the Tonkin Gulf.

The Tonkin Gulf is located between Vietnam and China, covering about 126,250 km2 with the largest breadth of about 310 km (176 miles) and the narrowest breadth of about 220 km (119 miles). The Gulf is home to many natural resources of seafood and oil and gas potentials, and an important sea route. For a long time, the people of the two countries have stared the use and exploitation in the sea of the Tonkin Gulf.

Based on the 1982 Convention, the two parties would demarcate the sea boundary in the estuary of the Beilun river, the boundary in the exclusive economic zones and the continental shelves in the Gulf. If both nations defined the exclusive economic zones and continental shelves of 200 nautical miles, so the distance between the coaslines of the two sides is less than 200 nautical miles, making most of the Tonkin Gulf become an overlapping area, and it is very difficult for management, exploitation, and protection.

In 1993, the two parties came to an agreement on the guiding principles for the demarcation  of the Tonkin Gulf, namely: "The two parties have agreed to apply international law and refer to international practices to negotiate the delimitation of the Tonkin Gulf; in order to reach an agreement on delimitation of the Tonkin Gulf, the two parties shall uphold the principle of equality and  take into account all relevant circumstances in the Gulf to reach an equitable solution." The agreement on the guiding principles is fully consistent with international law and practice.

From 1994 - 2000, the two parties conducted detailed talks in seven years. In negotiations, both parties exchanged views on international law applicable to specific circumstances and conditions of the Tonkin Gulf, taking into account the relevant natural circumstances, such as the length and direction, general morphology of the shoreline of each side, the presence and effect of the islands in the Gulf area, test of the fairness of the agreement in conformity with the modes applied by the International Court of Justice. The result is, the two parties have agreed on a delimited line connecting 21 points which, from point 1 to point 9, is the territorial sea border and, from point 9 to point 21, is  the common boundary in the exclusive economic zones and continental shelves. The maritime boundary in the Tonkin Gulf is of a total length of about 500 km.

In accordance with the demarcation line, Vietnam is entitled to enjoy 53.23% of the Gulf area, and China, 46.77%. In terms of area, Vietnam’s sea areas are about 8,205 km2 greater than China. The coastal islands in northeastern Vietnam were given partial effect, Bach Long Vi Island located far out in the Gulf, close to the boundary, but was given a 25% effect, and Con Co Island was given a 50% effect. All these results were achieved by the two parties thanks to the application of international law, including the use of the method of adjusting the median line and determined by the natural and objective conditions and geographical circumstances of the Tonkin Gulf. The test of equality, the ratio of coastline length of the two parties compared with the areas achieved were 1.1/1, as such the above result was equal.

This is the second agreement on delimitation, which Vietnam signed with a relevant country, but it is of a great significance because this was the first time in history, a common border line was delimited between the two countries in a large gulf, which is particularly important to all aspects for both countries, ensuring the fairness for both of them.

Cambodia

Vietnam and Cambodia are two neighboring nations, adjacent to each other. Both parties share the issue of clearly defining sovereignty over islands and delimiting the boundaries of territorial seas, exclusive economic zones and continental shelves.

In 1982, the two parties signed the agreement on the historical waters, in accordance with which, each party's sovereignty over the islands would be clearly defined in a line  conforming with the one proposed by the Governor of Indochina Brévié in 1939, a common historical sea area would be set up for joint control and management by the two parties, fisheries activities would be implemented in accordance with old customs, and all activities related to oil and gas exploration of one party ought to be approved by the other party.

Currently, the only outstanding issue remains between the two parties is to delimit a maritime boundary in the historic water and the territorial seas, and a maritime boundary in the exclusive economic zones and continental shelves.

In 1983, the Treaty on principles for settling the border problems signed between Vietnam and Cambodia clearly pointed out that the two parties would continue settling the outstanding problems in the spirit of equality, mutual respect for the benefits of the friendly and cooperative relationship between the two countries, in consistency with international law and practice.

Currently, both nations have expressed their commitment to respect the treaty and agreement on the borders signed by the two countries in 1980 and, on that basis, continue negotiating to settle the existing problem on border and territory so as to quickly build a border of peace, friendship and cooperation on land and on the sea between the two nations.

Indonesia

Indonesia is a neighboring nation having archipelagic status, which is located relatively far from Vietnam. There exists an outstanding issue of delimiting a common boundary in the exclusive economic zones and continental shelves between the two nations.

The overlap in the sea waters between the two countries is about 40,000 km2.

The two nations conducted negotiations for a settlement in 1978 on the basis of application of international law and practice into specific natural conditions in the relevant overlapping sea areas. In the process of settlement, both parties considered various aspects, such as the impact of the archipelagic status on the delimitation on the sea, the effects of Vietnam’s islands such as Con Dao and North Natuna Island of Indonesia, the length of the general direction of the coastline of each side, the natural prolongation of the continental shelves, the reasonable application of the median line... with a view to reaching an equitable solution.

After years of negotiations, Vietnam and Indonesia signed an agreement on demarcation of the continental shelves between the two countries in 2003.

The significance of the settlement of maritime boundary issues with the relevant states

Demarcation of maritime boundaries with the neighboring nations is a very important and sacred issue as it is related to the national sovereignty, sovereignty right, jurisdiction rights, and national interests. Also, this is a very new, complex and difficult issue.

A nation cannot impose its unilateral will on maritime boundary on another neighboring country which goes against international law and practice. The maritime boundary demarcation among the neighboring nations requires a strict application of international law and practice into specific natural conditions and circumstances; each country must defend the national sovereignty and interests of its own while respecting legitimate rights and interests of the neighboring nations, recognized by international law and practice.

The recent good settlement of border demarcation between Vietnam and the nations concerned constitutes the thorough grasp and correct policies of the Party and State of Vietnam in resolving border issues with the neighboring nations, negotiations for settlement in the spirit of respecting independence, sovereignty, equality, consistent with international law and practice, suitable to  the objective circumstances in order to achieve an equitable solution, acceptable to all parties concerned. The outcome of the negotiations have helped us to step by step define the scope and legal regime of the sea waters of Vietnam, creating favorable conditions for the use, exploitation and management, contributing to the socio-economic development of our country, strengthening the friendly and cooperative relations with the neighboring countries, reducing the risk of disputes and conflicts, maintaining peace and stability on the seas around our country./.