Battle of Vĩnh Yên The Battle of Vĩnh Yên ( ) , which occurred from 13 to 17 January 1951 , was a major engagement in the First Indochina War between the French Union and the Việt Minh . The French Union forces , led by World War II hero Jean de Lattre de Tassigny , inflicted a decisive defeat on the Việt Minh forces , which were commanded by Võ Nguyên Giáp . The victory marked a turn in the tide of the war , which was previously characterized by a number of Việt Minh victories . Prelude . By October 1950 , the Việt Minh had seized the initiative from the French . Operating from bases in the People ’ s Republic of China , Việt Minh troops under Giáp constantly raided French outposts along Route Coloniale 4 . At the end of the attacks on October 17 , the French had lost 6 , 000 troops , stunning the French government into action : the high commissioner for Indochina , Leon Pignon , and the commander - in - chief of the French Expeditionary Corps , General Georges Carpentier , were both recalled . Paris replaced them with General Jean de Lattre de Tassigny , widely considered one of the greatest French commanders after his spectacular leadership of the French First Army in World War II . De Lattre came to Hanoi , Vietnam , on 17 December and assumed both military and political control of French Indochina . The French Far East Expeditionary Corps numbered some 190 , 000 , including 10 , 000 serving in the French Air Force and 5 , 000 in the French Navy . The French occupied most of the country , but the Việt Minh held considerable portions of the countryside that allowed quick and easy access to various crucial points should the need arise . Giáp had five divisions , all armed and equipped by the Chinese , composed of about 10 , 000 troops each . Four of the five Vietnamese divisions were roughly 150 miles north of Hanoi , stationed around the Việt Bắc region near the Chinese border . The 320th Division was located southwest of the Red River Delta , which was controlled by the French . The dawn of 1951 heralded tremendous prospects for Việt Minh success . Giáp and Communist Party strategists planned for a massive offensive which would drive the French out of their homeland . Giáp decided to strike straight for Hanoi and chose Vĩnh Yên , 30 miles northwest of the capitol and the tip of the French defensive triangle , for the main blow . Battle . Dispositions . Vĩnh Yên was defended by two French mobile groups ( GM ) of 3 , 000 men each . GM 3 guarded the town itself whereas GM 1 held a series of key blocking positions to the east . Giáp hoped to drive a wedge between the two forces by pinning GM 3 against the Dam Vac lake to the south and then defeating the French in detail . In late December , Giáp had moved the 308th and 312th divisions from the Việt Bắc into position along the Tam Dao ridge . On January 13 , 1951 , he attacked . The battle . The 308th Division made a diversionary attack on Bao Chuc , a small outpost about two miles north of Vĩnh Yên . GM 3 quickly moved north to relieve the beleaguered 50 - man garrison , but they were ambushed by forces from the 312th Division at Dao Tu . A series of heavy air strikes and artillery barrages eventually allowed GM 3 to disengage and return to Vĩnh Yên , but not before it had lost an entire battalion and had another severely damaged . Việt Minh forces followed their success by taking a string of hills in front of Vĩnh Yên . On 14 January , de Lattre arrived in Vĩnh Yên to take personal command of the fighting . He ordered GM 2 to come from Hanoi as a reserve , GM 1 to attack west and break through to the town , and also called for heavy air strikes along with more reinforcements . GM 1 managed to successfully advance along Route 2 and joined GM 3 for a number of attacks which drove the Việt Minh out of the hills they had recently captured . On 16 January , however , the Việt Minh launched a massive human - wave assault with the entire 308th division . De Lattre replied by ordering the largest French air strike of the entire war , in which napalm was used for the first time on a large scale . Giáp ’ s troops initially fled , only to come back and continue fighting . In the early hours of 17 January , French soldiers on Hill 101 ran out of ammunition and withdrew , soon followed by the Việt Minh capture of Hill 47 . Giáp now had control of the center while the French controlled hills 210 and 157 on the flanks . At dawn , the 308th Division attacked again . De Lattre used GM 2 , his last reserve , to support Hill 47 while GM 3 was sent to the isolated French position on Hill 210 . More air and napalm strikes followed both attacks . Finally , French aerial forces proved decisive . The 308th Division began to retreat and the 312th launched one more desperate attack to reverse the decision , but it was too late . By noon on 17 January , both Việt Minh divisions scrambled for the mountains . Aftermath . Although the impressive French victory did not provide any short - term reprieve — Giáp would try to breach the line again shortly — it was a morale booster for French forces and confirmed that Paris had made the right decision in picking de Lattre to lead the effort against the Việt Minh . Strategically , the battle meant that the war would go on and ultimate victory would not be easy for either side .