The East Sea is a semi-enclosed sea, with an area of about 3.5 million square kilometres. It is one of the largest seas in the world, located between latitude 0⁰ and latitude 25⁰ North and longitude 100⁰ East to longitude 121⁰ East. It is bounded by Vietnam in the west, the islands of Luzon, Palawan in the east, China in the north, and the Borneo Island and Indonesia in the south and southeast. It communicates with the East China Sea via the Taiwan Strait in the north; with the Philippines Sea (of Pacific Ocean) via Luzon strait in the East; with the Andaman Sea (of the Indian Ocean) via the Singapore and Malacca Straits in the southwest; with Java Sea via the Strait of Karimata in the south.

East Sea, the shortest route connecting the Indian Ocean with the Pacific Ocean, acts as a gateway for international trade. Here, the Strait of Malacca with a length of 600 nautical miles and a width of only 1.2 nautical miles at its narrowest point, connecting the seaports of Northeast Asia, the West coast of America with South Asia, Africa, the Middle East, Southern Europe, is forecast to be more overloaded due to the increase in global trade and energy needs. The international shipping route through the East Sea is considered the 2^nd busiest one in the world (only after the Mediterranean), accounting for more than half of the global maritime trade shipping tonnage which is crucial for not only its surrounding countries and territories, but also for the East Asia and the world.

In addition, the oil, gas, minerals, and seafood reserves in the East Sea can ensure significantly energy and food security for its adjacent countries. According to preliminary assessment of scientists, the oil and gas reserves in the East Sea can exceed those in the Middle East region. The most potential areas for oil are the continental shelf of the Spratly and Paracel Islands, and the Gulf of Tonkin. As for seafood resources, according to the Food and Agriculture Organisation of the United Nations, the East Sea is ranked 4^th out of 19 best fishing grounds in the world in terms of annual total catch. East Sea is believed to be home to more than 1,000 species of fish, 90 species of shrimp and 70 species of molluscs. Fishery is a very important economic sector for countries around the East Sea. Every year, as many as 06 million tons of seafood are caught here, equivalent to 10% of the total volume of seafood caught worldwide.

For Vietnam, the East Sea plays an important role in the cause of national construction and defence both in history, present and future. Not only providing a source of food for coastal residents for thousands of years, the East Sea also makes it easy for the development of economic sectors and is a commercial gateway for Vietnam to regional and international markets. Moreover, East Sea is crucial for Vietnam to sustainably develop its key economic sectors, such as fisheries, petrolium, maritime traffic, shipbuilding, tourism, etc. In addition, the coast of Vietnam also carries great potential for placer ores, such as coal, zircon, tin, gold, rare earth etc., in which heavy sand and black sand are valuable resources of the country. The Spratly and Paracel Islands are located in the center of the East Sea which is favourable for the placement of information stations, air traffic control, navigation, stopping and refueling plots for ships, boats, etc. on this maritime route and hold special importance for national defence in sea direction.

PHAM BINH