The largest South Korean operation to date starts, forming a link-up of two Korean division areas of operations along the central coastal area of South Vietnam.
South Korean forces had been in South Vietnam since August 1964, when Seoul sent a liaison unit to Saigon. The South Korean contingent was part of the Free World Military Forces, an effort by President Lyndon B. Johnson to enlist allies for the United States and South Vietnam. By securing support from other nations, Johnson hoped to build an international consensus behind his policies in Vietnam. The effort was also known as the "many flags" program. The first South Korean contingent was followed in February 1965 by engineer units and a mobile hospital. Although initially assigned to non-combat duties, they came under fire on April 3 when the Viet Cong attacked them.
In September 1965, in response to additional pleas from Johnson, the South Korean government greatly expanded its troop commitment to Vietnam, agreeing to send combat troops. By the close of 1969 there were over 47,800 Korean soldiers actively involved in combat operations in South Vietnam. Seoul began to withdraw its troops in February 1972, following the lead of the United States as it drastically reduced its troop commitment to South Vietnam.