South Vietnamese soldiers under the Roman Catholic President Ngo Dinh Diem open fire on Buddhists defying a ban on the flying of the Buddhist flag on Vesak, killing nine and sparking the Buddhist crisis.

The Hu Pht n shootings were the deaths of nine unarmed Buddhist civilians on 8 May 1963 in the city of Hu, South Vietnam at the hands of the army and security forces of the government of Ng nh Dim, a Roman Catholic. The army and police fired guns and launched grenades into a crowd of Buddhists who had been protesting against a government ban on flying the Buddhist flag on the day of Pht n, which commemorates the birth of Gautama Buddha. Dim denied governmental responsibility for the incident and blamed the Vit Cng, which added to discontent among the Buddhist majority.

The incident spurred a protest movement by Buddhists against the religious discrimination which they felt was perpetrated by the Dim regime, known as the Buddhist crisis, and this led to widespread civil disobedience among the South Vietnamese. Leaders of the army conducted a coup on 1 November 1963, after six months of tension and growing opposition to the regime; this led to the arrest and assassination of Ng nh Dim on 2 November 1963.

The Army of the Republic of Vietnam (ARVN; Vietnamese: Lục quân Việt Nam Cộng hòa; French: Armée de la république du Viêt Nam) were the ground forces of the South Vietnamese military from its inception in 1955 to the Fall of Saigon in April 1975. It is estimated to have suffered 1,394,000 casualties (killed and wounded) during the Vietnam War.The ARVN began as a postcolonial army that was trained by and closely affiliated with the United States and had engaged in conflict since its inception. Several changes occurred throughout its lifetime, initially from a 'blocking-force' to a more modern conventional force using helicopter deployment in combat. During the American intervention, the ARVN was reduced to playing a defensive role with an incomplete modernisation, and transformed again following Vietnamization, it was upgeared, expanded, and reconstructed to fulfill the role of the departing American forces. By 1974, it had become much more effective with foremost counterinsurgency expert and Nixon adviser Robert Thompson noting that Regular Forces were very well-trained and second only to the American and Israeli forces in the Free World and with General Creighton Abrams remarking that 70% of units were on par with the US Army. However, the withdrawal of American forces by Vietnamization meant the armed forces could not effectively fulfill all of the aims of the program and had become completely dependent on U.S. equipment since it was meant to fulfill the departing role of the United States.At the ARVN's peak, an estimated 1 in 9 citizens of South Vietnam were enlisted, and it had become the fourth-largest army in the world composed of Regular Forces and the more voluntary Regional and Village-level militias.Unique in serving a dual military-civilian administrative purpose, in direct competition with the Viet Cong, the ARVN had also become a component of political power and suffered from continual issues of political loyalty appointments, corruption in leadership, factional infighting, and occasional open internal conflict.After the fall of Saigon to North Vietnam's People's Army of Vietnam (PAVN), the ARVN was dissolved. While some high-ranking officers had fled the country to the United States or elsewhere, thousands of former ARVN officers were sent to re-education camps by the communist government of the unified Socialist Republic of Vietnam. Five ARVN generals committed suicide to avoid capture by the PAVN/VC.