Early 1952, Captain Đổng was appointed Commander of the 55th Vietnamese Battalion (55e BVN) stationed at the Nà Sản fire-base. In late November, using 3 battle-hardened divisions (308th, 316th and 320th) General Giap attacked Nà Sản with the intention of defeating the French Union forces to take control of northwest Tonkin. The 55e BVN fought valiantly against the enemy's relentless assaults. To put an end to the "human wave", Đổng ordered his artillery-support to level and to fire howitzers loaded with fragmentation shells directly at the enemy troops. His decision saved the battalion and earned him a promotion to Major.