The bloody campaign in the remote, mountainous valley in northwestern Vietnam pitted Vo Nguyen Giap, the 42-year-old father of the popular Vietnamese army, the Viet Minh, against Christian de la Croix de Castries, a colonel in the armoured division and head of the French garrison at Dien Bien Phu.

The former, a strategist of guerrilla warfare, was born into a well-off peasant family and brought up on a diet of Confucianism and nationalism. The latter was an ex-cavalryman from a famous French aristocratic family.

The French garrison at Dien Bien Phu was born out of a decision by General Henri Navarre, France's military commander in Vietnam, to provoke a full-scale battle with the Viet Minh to crush them once and for all.

Five hundred kilometres (310 miles) northwest of Hanoi along the Lao border, Dien Bien Phu was considered an ideal place to draw the guerrilla army into a fight, as well as disrupt their supply routes from Laos and China.

The Vietnamese, however, were determined to score a major victory on the battlefield to reinforce their position in discussions underway to end the war.

After the French began building their entrenched position on the valley's large plain in November 1953, assembling some 15,000 French, North African, pro-French Vietnamese and foreign legionnaires, the Vietnamese Politburo gave the green light for an assault.

Originally planned for January 25, Giap took a critical decision to call off the attack in the face of opposition from his Chinese advisers and own officer corps, saying he did not feel his troops could secure an outright victory.

Subsequent recruitment and conscription enabled him to boost the troops under his command to around 50,000, giving him the numerical advantage he sought.

The bloody battle eventually began on March 13 and raged until the last exhausted and shell-shocked French defenders hoisted the white flag on May 7.

But the fate of the French side was effectively sealed over a 36-hour period on March 13 and 14 with the loss of the two key hills of Him Lam and Doc Lap overlooking the valley.

With these in Viet Minh hands, the French had lost the high ground they needed, and now sat defenseless in the sights of Vietnamese gunners manning 105mm artillery and anti-aircraft guns.

Giap, having used 260,000 conscripted civilian porters to haul food, weapons and ammunition onto camouflaged hill positions, had already won the battle that was to come.

The following weeks were punctuated by a furious series of assaults and counter-attacks. The French could only wait for the end in agony, short of ammunition and rations, hoping for reinforcements to come in by parachute after the airstrip was destroyed on March 28.

The end came on May 7, when the Vietnamese captured the last hill in their way, dynamiting the French bunker and taking out survivors with grenades. At 5:30 pm, de Castries surrendered. He was released four months later.

"The Battle of Dien Bien Phu was a modern military engagement and a victory for what had only a few years earlier been a guerrilla army," according to Christopher Goscha, an historian at the University of Lyon II.

It was less the result of French weakness than the organizational abilities of the Viet Minh and their success in "executing a modern battle," Goscha said in October's edition of the Journal of Southeast Asian Studies.

But it came at a cost to both sides. Around 3,000 French troops died or disappeared and 10,000 were captured. As many as 10,000 Vietnamese soldiers died, historians say.

WAR.WIRE