In 1963, Phạm Thanh Tâm began his art education at the Vietnam Fine Arts College. While studying, Tâm volunteered for the front in South Vietnam where he was given permission to write and paint under the qualification of an artist for the People’s Army of Vietnam (PAVN). From this time, he continued to use his writing nom de plume, Huỳnh Biếc. In the north, he also helped at sea in Hạ Long Bay. His paintings depicted the caves and shelters along the Ho Chi Minh Trail and the liberation of Đà Nẵng and Saigon in the south, as well as the mountainous regions of the north, Hạ Long Bay and Hanoi. He graduated the Vietnam Fine Arts College in 1967 as an oil painter alongside other notable future artists Trịnh Quốc Thụ, Quang Phương, Nguyễn Thanh Châu and Phạm Đỗ Đồng.
Tâm captured the occasion he visited Division B320 (fig. 1). This division was a mobile unit, thus the artist could not remember its exact location. The soldier in the sketch was practising putting a machine gun on his shoulder to march. At the time in 1965, soldiers in North Vietnam were engaged in combat against American forces. Northern soldiers also received training to prepare for their march to South Vietnam on foot via the Ho Chi Minh Trail in harsh conditions.
Tâm remembered the sketch was probably made at Xuân Mai, Hoà Bình Province, near Hanoi; its mountain terrain was suitable for training activities to prepare for the march south.
The Ho Chi Minh Trail, or Route 559, was founded in May 1959. This sketch was made in 1964, but the route was still unfinished after nearly 5 years. Therefore marching along the trail was extremely arduous. It required climbing up steep slopes and wide passes for many days. As the journey would take close to three months, soldiers practised for the march by carrying heavy backpacks filled with bricks. On the march itself, the bricks were replaced by rice, clothes, military equipment and weapons.