The Northeastern region of Dai Viet where big rivers interlink with each other is favourable for domestic watery traffic and foreign trade through the river mouths, notably the Luc Dau Giang point where merge the six rivers, namely: Chanh, Kenh, Nam, Gia, Da Bach and Bach Dang. Because Bach Dang river mouth connect the Northeastern sea with the inland areas, it is possible to approach the inland areas from the East Sea. Moreover, this area is also home to dense forests, sand dunes, casuarina stands, mangrove swamps and hundreds of big and small islands making its terrain naturally dangerous and of great significance in military. People in the Northeastern region had strong sense of community as they had to deal with the harsh natural conditions and foreign invaders together. They were absolutely loyal to the king and determined to fight the enemy for Homeland protection.

Stemming from this geographical features, when invaded our country, besides the inland troops approaching through the land border, Chinese feudal dynasties used to deploy a seaborne column to penetrate through the big river mouths, such as Bach Dang river mouth in order to form up pincer assault. This is because a seaborne attack would bring them various advantages, namely: secrecy, surprise factor, easy to deploy a large number of troops and food. In 938, the Southern Han troops deployed a big column with hundreds of ships to invade our country through the Bach Dang river mouth. When entering this point, the Southern Han troops were totally destroyed by our people and troops under the leadership of Ngo Quyen. This put an end to 1000 years of dependence for our country. In 981, Song dynasty sent a large number of marine troops invading our country through Bach Dang river mouth and were heavily defeated by our people and troops under the  command of Le Dai Hanh. Yuan troops, who were very skillful at mounted warfare and had conquered a vast area in Asia and Europe, suffered three defeats when invaded our country and had to withdrew along the waterways to the sea. Especially in their third invasion to our country in 1288, the Yuan deployed an overwhelming naval troop attacking our country from the sea. However, just a few days later, Dai Viet troop and people in the Northeastern region, under the command of General Tran Khanh Du, successfully ambushed their logistics corps, capturing a large number of food, weapon and prisoners of war. This victory was an important premise for the people and troop of Tran Dynasty defeated the Yuan troop on the Bach Dang river later, annihilating their will of invading Dai Viet, bringing long lasting peace to the country.

Why Vietnam could feudal dynasties win landsliding victories on the Bach Dang river and coastal areas in the Northeastern region? Was it because of their talents in establishing the combat posture in the region? This posture was manifested in the following aspects:

First, issuing favourable policies encouraging people to carry out land reclamation and build new residential areas in the coastal regions in combination with establishing defence posture to protect the coastal areas. This policy was applied creatively and effectively by the feudal dynasties in the construction and protection of the country, especially in building the defence posture in the Northeastern sea and island and coastal regions. Accordingly, the feudal dynasties all defined sea borders and dispatched their offsprings and relatives to some localities to exercise control of the borders. They also allowed their mandarins to employ poor people and prisoners to reclaim new land, build plantations and coastal villages and founded their own troops. Particularly, the Ngo and Dinh Dynasties issued several favourable policies to encourage people living in the coastal provinces of Thai Binh, Nam Dinh, Ninh Binh, Thanh Hoa to reclaim coastal land for cultivation and military purposes. The Early Le Dynasty determined sea border with the Song Dynasty and posted his adopted son to take control of Phu Dai (Vinh Bao, Hai Phong). The Ly Dynasty had favourable policy for remote areas with the aim of easing the people and encourage them to settle down in the islands (now Van Don) and develop into commercial port for foreign trade. Tran Dynasty inherited and developed the policies as dividing the sea into Hai Dong and Hai Tay for protection and management and developing Van Don port into a big one which is of military significance and exercising strict control of the port for fear of foreign spy. Besides, the forces stationing in the islands and border areas had also to involve in land reclamation for the establishment of installations and food production for self-sufficiency.

After winning Ming troops, with the guideline of “protecting the country since it is still not in danger”, the kings of the early Le Dynasty attached importance to protecting the Northeastern coastal region by: dispatching their trustworthy, loyal and capable mandarins to occupy the crucial areas in the Northeast; renovating traffic and irrigation systems; and developing trade. Under the Nguyen dynasty, the protection of seas and islands was legalized which clearly ruled the responsibility of mandarins, troops and people. Besides, there were also policies for improving living standard of coastal people and strengthening defence in coastal areas.

The establishment of plantations and installations in the coastal areas is one way to combine military operations with economic development which is a prime policy of feudal dynasties in the construction and protection of the country. Thereby, the supply of food for troops is made sufficient; troops were recruited from the locals. They were connected with each other and involved in production to supply for training and  accumulate food in preparation for war.

Second, developing marine troops, building warships, producing weapons, training troops and strengthening defence in the islands, river mouths, and conducting patrol along the borders. In face of the invasion plans of Chinese feudal dynasties, our feudal dynasties strengthened vigilance and carried out policies to safeguard the countries, such as: deploying troops to key areas like river mouths or islands; conducting land and sea patrol and control. They also placed emphasis on developing the infantry and naval troops to make them seasoned and dispatched appropriate amounts of troops to localities to establish combat posture. Besides, they also paid attention to producing weapon and building warships, training troops, and exercising on a periodical basis and in a strict manner suitable to the situation and limiting foreign trade within the area of Van Don island.

Together with issuing policies to consolidate the communities to generate the aggregate strength of the entire nation to establish a posture for countering the enemy on the coastal areas of the Northeastern region, the feudal dynasties also carried out flexible and resolute foreign policies to keep good relations and prevent the risk of war with China’s feudal dynasties.

The above lessons are still of value until nowadays and they should be further studied and applied in the building of defensive areas and the all people’s national defence associated with the all people’s security posture for Fatherland protection.

Colonel Canh Chi Cuong, MA., The Department of Strategies, National Defence Academy