In March 1971, Nguyễn Ðức Thọ – much like artist Bùi Quang Ánh– was stationed in Tchepone (Sepon or Xépôn) in Laos. Situated in the eastern part of Savannakhet Province, Tchepone was part of the front line of Operation Lam Sơn 719, approximately 26 kilometres from the Battle of Bản Đông.
Operation Lam Sơn 719
In the Lam Sơn 719 Campaign, US and Army of the Republic of Vietnam (ARVN) forces used helicopters carrying airborne soldiers to reach high positions. Using superior firepower to take over the surrounding areas, US and ARVN units attempted to interdict enemy movement. The intended result was to prevent military supplies from North Vietnam reaching their forces in the Republic of Vietnam (RVN).
PAVN Defensive Positions
Thọ captured the defensive capabilities of the People’s Army of Vietnam (PAVN) in Tchepone (fig. 1).

The artwork depicts PAVN air defence soldiers with a 12.7mm Soviet-origin DShK heavy machine gun waiting for the enemy. After learning of Operation Lam Sơn 719, North Vietnamese forces implemented an emergency strategy. They occupied Tchepone high points in advance. They then installed camouflaged units with heavy machine guns waiting to target low-flying helicopters, aircraft and ground forces.
Battle of Attrition
During Operation Lam Sơn 719, American helicopters flew more than 160,000 sorties and ARVN helicopters a further 5,500. More than 168 helicopters were destroyed and 618 damaged (according to the US-based Vietnam Helicopter Pilots Association). The operation collapsed in the face of heavy opposition and the PAVN’s determined resistance. The Ho Chi Minh Trail remained open.

As an aside, high point 495 at Tchepone was on the northern bank of the Sepon River (Sông Xê-pôn). The Sepon River forms the border between Vietnam and Laos, separating Quảng Trị Province from Savannakhet Province in Laos. Many places had no names, so high point 495 was just a location number marked on PAVN military maps.