Battle of Lang Son (1979)

Battle of Lạng Sơn
Part of the Sino-Vietnamese War
A Vietnamese soldier armed with an RPG-7 grenade launcher defending Lang Son in 1979
Date 17 February–16 March 1979 Location Lạng Sơn and vicinity, northern Vietnam Result Chinese strategic pyhrric victory Vietnamese tactical victory
Belligerents
China	Vietnam
Commanders and leaders
Xu Shiyou	Hoàng Đan Nguyễn Duy Thương
Units involved
43rd Army 50th Army Unit 56037 Unit 56039 Unit 56229 54th Army 55th Army	3rd Division 327th Division 337th Division 338th Division 166th Artillery Regiment 272nd Anti-Aircraft Regiment Militia, regional, and border guard units
Strength
~130,000 regulars, unknown number of tanks	By 17 February: ~13,000 regulars, militia, regional troops and border guards By 6 March: 3 regular divisions
Casualties and losses
Chinese source: 1,271 killed 3,779 wounded Vietnamese source: ~19,000 casualties	Vietnamese source: 3rd Division: 6.6% killed, 8.4% wounded (equivalent to 660 killed and 840 wounded) 327th Division: no data 337th Division: 650 killed 338th Division: 260 killed Chinese source: 10,401 casualties

43rd Army
50th Army

The Battle of Lang Son was fought during the Sino-Vietnamese War, days after the Chinese People's Liberation Army (PLA) advanced 15 to 20 kilometers deep into the northern provinces of Vietnam. The fighting occurred primarily at the city of Lạng Sơn, a few kilometers from the Sino-Vietnamese border. Although the Chinese eventually occupied Lạng Sơn and its nearby vicinities during the battle, it proved during that time that the Chinese regular units invading northern Vietnam were no match against militia and irregular Vietnamese units tenaciously harassing the Chinese advance southward to Hanoi, Vietnam's capital city, and eventually took Chinese forces days to occupy the city and dislodge its defenders.

After capturing the northern heights above Lạng Sơn, the Chinese surrounded and paused in front of the city in order to lure the Vietnamese into reinforcing it with units from Cambodia. This had been the main strategic ploy in the Chinese war plan as Chinese leader Deng Xiaoping did not want to risk an escalation potentially involving the Soviet Union. The Vietnam People's Army (VPA) high command, after a tip-off from Soviet satellite intelligence, was able to see through the trap, however, and committed reserves only to Hanoi. Once this became clear to the PLA, the war was practically over. An assault was still mounted, but the Vietnamese only committed one VPA regiment defending the city. After three days of bloody house-to-house fighting, Lạng Sơn fell on 6 March. The PLA then took the southern heights above Lạng Sơn

As part of the punitive expedition against Vietnam for the occupation of the pro-Chinese Democratic Kampuchea, Chinese forces entered northern Vietnam and advanced quickly about 15–20 kilometers into Vietnam, with fighting mainly occurring in the provinces of Cao Bằng, Lào Cai and Lạng Sơn. The Vietnamese avoided mobilizing their regular divisions into the fight, using most of them for the defense of Hanoi. The Vietnamese forces tried to avoid direct combat, and often used guerrilla tactics to harass the Chinese forces advancing southwards. To make this work for the Vietnamese, they had to use their mountainous terrain to their advantage, which was a serious handicap for the Chinese trying to assault and destroy several Vietnamese irregular units.

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