The PAVN 4th Army Corps Command selected Dầu Tiếng–Chon Thanh as the first target for their operation, as it was the weakest point in the South Vietnamese defensive line in the north-west area. South Vietnam maintained four Regional Force (RF) battalions (35th, 304th, 312th and 352nd Battalions) totalling 2,600 soldiers in the area, along with one armored brigade and ten 105 mm artillery guns. The military zone of Dầu Tiếng–Chơn Thành was located adjacent to the three provinces of Tây Ninh, Bình Dương and Binh Long. The task of capturing Dầu Tiếng–Chon Thanh was entrusted to the PAVN 9th Infantry Division, whose strength were bolstered by the 16th Infantry Regiment, the 22nd Armored Battalion, one artillery battalion and one air-defence battalion. At 05:00 on 11 March the 9th Infantry Division commenced its attack on Dầu Tiếng. ARVN artillery positions in Rung Nan, Bau Don and Cha La were the primary targets of the 9th Infantry Division on the first day of the attack.