Guerrilla Tactics tunnel In December 1965, Ho Chi Minh and the North Vietnamese leadership ordered a change in a way the war in the South was to be fought. From now on, the Vietcong would avoid pitched battles with the Americans unless the odds were clearly in their favor. There would be more hit and run attacks and ambushes. To counter the American build-up, Vietcong recruitment would be stepped up and more North Vietnamese Army troops would be infiltrated into South Vietnam. The Vietcong, following the example of Chinese guerillas before them, had always given the highest priority to creating safe base areas. They were training grounds, logistics centers and headquarters. They also offered secure sanctuaries for times when the war might go badly. Hiding the base areas had always been a high priority for the Vietcong. Now, with American spotter planes everywhere, it was more vital than ever to protect them. In remote swamps or forests, there were few problems, but nearer the capital, it was much more difficult. The answer was to build enormous systems of underground tunnels. The orders coming from NLF headquarters were absolutely clear. Tunnels were not to be treated as mere shelters. They were fighting bases capable of providing continuous support for troops. Even if a village was in enemy hands, the NLF beneath were still able to conduct offensive operations. There were complexes big and small scattered across the country. Each villager in a NLF area had to dig three feet of tunnel a day. There was even a standard handbook specifying how tunnels were to be built. The biggest tunnel systems were in the Iron Triangle and the Cu Chi District, only 20 miles from Saigon.