Against the Song's plan of "a rapid invasion like thunder so that the opposition could not even have time to cover their ears" in 981, Dai Co Viet's military and people under the command of King Le Dai Hanh united in smashing the Song dynasty’s scheme for attacking Dai La Citadel and capture Hoa Lu so as to firmly protect the kingdom of Dai Co Viet.

Taking advantage of the murder of the King Dinh Tien Hoang and his son Dinh Lien, the Song dynasty decided to invade Dai Co Viet. In order to realise this plot, the Song dynasty mobilised generals and soldiers, formed armies, appointed Hou Renbao as commander of the advance force, Yang Wenjie as commander of the ground force and Liu Cheng as commander of the navy. With its  "powerful forces and skillful commanders", the Song dynasty hoped to defeat the military and people of Dai Co Viet with sudden, rapid attacks and make us unable to resist, thereby easily gaining victory. In 981, the Song dynasty invaded Dai Co Viet by land and sea, attacking Dai La citadel and then Hoa Lu. The enemy’s advance force commanded by Hou Renbao manoeuvred from Yong Zhou to Ngan Son and Dai La. The second ground force commanded by Yang Wenjie manoeuvred from Yong Zhou to Lang Son and Dai La. The navy as the last force led by Liu Cheng sailed from Guangzhou to Bach Dang river and then joined up with the two armies to attack Dai La and Hoa Lu.

Wooden stakes in the Bach Dang river used in the naval battle of 981 between the military of Dai Co Viet and the Song invaders (photo: baotanglichsu.vn)

In the face of the Song invasion, since the 6-year-old King of Dinh Toan was too young to manage the country's affairs, Queen Duong Van Nga appointed the ten-thousand man army Commander Le Hoan as the commander-in-chief to prepare for a resistance war. In the autumn of 980, during the court’s meeting to discuss tactics to fight against the enemy, with the support from generals, soldiers, and senior officials, for the sake of the country’s survival, the Queen put aside her family’s business to transfer power to Le Hoan. After ascending the throne, on the one hand, Le Hoan continued to consolidate the dynasty and urgently prepared for a resistance war; on the other hand, he sent an envoy to the Song dynasty to deliver Dinh Toan’s abdication as an opportunity to understand the enemy’s strength and find ways to delay its invasion. Despite the diplomatic efforts of the Le Dynasty, the Song dynasty was determined to annex Dai Co Viet. With his talent, King Le Hoan and his staff organised and encouraged the military and people of the whole country to create the synergy for defeating the Song invasion. The victory over the Song invaders showed the spirit of solidarity between the Le Dynasty and the people, while proving art of war of the High Command during the resistance war.

First of all, implement the policy of "encouraging all people to develop the country in peacetime and mobilising all citizens to fight the enemy in wartime." After vanquishing the upheavals of 12 warlords and unifying the country, Dinh Tien Hoang had established a central government and divided the country into 10 circuits (each circuit is equivalent to a province today). In addition, the King also had established ten armies (in all 10 circuits): “in the 5^th year of his reign (974), Dinh Tien Hoang founded 10 armies, each included 10 brigades, each brigade included 10 companies, each company included 10 sections, each section had 10 soldiers.” At that time, his kingdom should have had 100,000 troops, but in fact this was only the predetermined military organisation structure (ten armies) to mobilise the maximum human resources of the country for fighting against invaders and defend the kingdom.

Inheriting the valuable legacy of the Dinh Dynasty, with his fighting experience as a general, King Le Dai Hanh enlisted citizens as soldiers and employed strong men to the guard. At the same time, he ordered the armies to urgently form militia units tasked with suppressing rebellion, protecting the people, readily combating the invaders. In case the enemy was so strong that the armies were unable to cope with, their task was to slow down its advance, block its approach to the imperial capital, and wait for the imperial forces to come and fight. In addition, the King also encouraged villages to build up militia teams, consisting of healthy men who still worked in the field and lived with their families, but in turn they took charge of guarding and safeguarding their villages. When the invaders came, they joined the armed forces in defending the kingdom. Those actions proved Le Dai Hanh's ability to rule the kingdom and his strategies. The people described him as "the King who led the people to combat the Song invaders, and pacify the Champa Kingdom and gained admiration from ethnic minority groups." According to the people, “the King dedicated himself to improving the people’s daily life, serving the kingdom, fostering agriculture, and carefully guarding the border.”

Thus, in the time of Dinh and Le Dynasties, Dai Co Viet’s armed forces, including the imperial guard, the King's army and the militia were regularly built up. It was the deployment of troops as the ordinary people that helped the King to reduce the burden of spending but ensure the strength of the armed forces to respond to sudden attacks of the enemy much more powerful than themselves.

Secondly, select and build decisive positions that were favorable for both attack and defence. Understanding the Song dynasty's plot of an invasion, the Le King and his people proactively worked out a detailed plan and organised troops to intercept the enemy right from the border and along the roads, which would help prevent them from joining forces and supporting one another. To realise that plan, our forces selected and built decisive combat positions that were firm and easy to deploy and cover troops. For his part, King Le Dai Hanh directly conducted surveys to understand the situation and terrain, discover the waterways and roads of military value that the enemy was expected to pass through, and then build defensive and counter-attack positions. The chosen places were the ones with natural obstacles favourable for us to organise defence, launch attacks, mobilise forces, assure sustainment, and bring into play the synergy of forces and weapons. The first chosen place was (1) Binh Lo (at the end of Tam Dao mountain range, in Da Phuc, Soc Son, Hanoi today) - a high promontory like a horseshoe, the widest part was over 700 m, with more than 2/3 of the whole area was surrounded by Ca Lo river, creating a natural ditch blocking the enemy. The rear part was a jungle favorable for ambushing the enemy. There, King Le Dai Hanh built a defensive fortification system - a citadel as solid support for his troops and people to intercept the enemy's advance force. (2) Another chosen place was Tay Ket (Viet Yen, Bac Giang province) - a large area in the south of the Tay Ket field whose terrain was favorable for the deployment of the imperial troops and militia forces to destroy a large number of enemy troops. (3) The last chosen place was Bach Dang River. “The Bach Dang River, aka the Van Cu River, is more than 2 miles wide with many river branches. On the banks are high mountains and dense bushes. It is a good place on the sea route.” Making use of the position of Bach Dang River, inheriting and applying creatively Ngo Quyen’s experience in combating the Southern Han army, King Le Dai Hanh set up solid wooden stakes to prevent the enemy's naval force from the sea, while secretly deploying his naval and ground forces to ambush the enemy in the river and on both banks.

Thirdly, organise forces reasonably in directions and areas to intercept the enemy. In order to thwart the Song’s scheme of using the advance force to quickly smash the military and the people of Dai Co Viet and its plan to join forces to conquer Dai La and Hoa Lu citadels, the Le King and his people chose the enemy's first army led by Hou Renbao to destroy. This army was headed by a disciplined, ambitious, reckless, aggressive general with great determination to carry out the Song dynasty's plan. Defeating this army and killing its commander would quickly undermine the enemy’s combat morale and invasion plan. In the direction of Ngan Son - Dai La, the King himself directly commanded the imperial and militia forces to intercept the enemy at Binh Lo and prevent them from advancing toward Dai La and Hoa Lu. At Binh Lo, there was a decisive battle between our military and the enemy, we won victory, and the enemy was forced to retreat to Ninh Giang. After the battle of Binh Lo, King Le Dai Hanh set up an ambush in Do Lo river; the enemy's advance force fell into our trap, maneuvered from Ninh Giang down to this river and was destroyed. This victory led to the collapse of the enemy's plan of using an advance force to raid our forces, caused panic amongst enemy troops, and sapped their fighting morale.

In the Bach Dang River, our High Command did not deploy a large number of troops, but it managed to block the enemy's advance. In reality, after crossing the northeastern sea into Bach Dang river, the Song navy led by Liu Cheng was attacked by our military and people and suffered from heavy losses; therefore, it had to flee back to its country instead of advancing.

In the direction of Lang Son - Dai La, Tun Huang Xing in Hoa Bo refused to deploy his infantry troops, waiting to join Liu Cheng’s force to attack Dai La and Hoa Lu; only the ground force commanded by Chen Kangdao reached Tay Ket for occupying Dai La. Knowing that Hou Renbau's advance force and Liu Cheng's navy had been crushed, Tun Huang Xing’s army was panicked and immediately retreated. Chen Kangdao’s army in Tay Ket was isolated without support or reinforcement. Seizing the opportunity, "the King ordered his generals to hunt down and destroy the invaders. As a result, troops of Chen Kangdao suffered a heavy loss with more than half of them being killed and their remains being piled up on the field. Two commanders of the enemy, namely Guo Quanbian and Zhao Fenghuan were captured and brought to Hoa Lu." The counterattack of the Le King and his people at Tay Ket dealt a death blow to the Song dynasty’s Southward conquest and completely victoriously ended the resistance war to protect the kingdom.

The victory of the resistance war against the first Song invasion which took place more than a thousand years ago provides us with many valuable lessons. The lessons on promoting the aggregate strength of the entire nation with the imperial and militia forces playing a core role, setting up defensive positions, organising and using forces to combat the enemy should continue to be studied and creatively applied to building the all-people national defence, the postures of all-people’s national defence and people's security posture, the armed forces and defensive zones so as to make contributions to safeguarding the Fatherland.

Sr. Col HOANG MANH DU, National Defence Academy