Completing the Narrative on Vietnam(SM).   Thomas F. Pike

What a visit with a former Viet Cong taught me
about tunnels in a counterinsurgency

I have traveled to Vietnam numerous times to research the Vietnam War since my first visit to Hue City in 1996. I have started to research bases and tunnel systems during recent visits and have come to realize that this strategy had a greater impact on the war than I originally thought.

We tend to think that tunnel complexes were only in Cu Chi, an NVA and VC base north of Saigon in Vietnam's III Corps. This is actually not true. Forty miles south of Da Nang in an area called the Que Son Valley, I have counted numerous complexes, capable of holding a squad of VC up to a full NVA Battalion. In 2017 I visited a tunnel system north of Tam Ky. This tunnel system probably spanned 150 square kilometers and connected several villages just north of the capital of Quang Tin Province. The VC intentionally dug tunnels under bamboo orchards because they knew they were a barrier to U.S. tanks and APCs. The bamboo itself could conceal breathing holes as well.

During a recent trip to Da Nang, a former Viet Cong officer showed me the entrance to a tunnel system under his house. He was only 500 meters from the outer perimeter of the Marble Mountain Air Facility in Da Nang. Entrances to the tunnels in his village were so well camouflaced, they would have taken hours of focused effort to uncover. South Vietnamese security forces never found his tunnel

There are lessons learned from this counterinsurgency we can apply today. First, commanders will have to accept that tunnels will remain an integral part of an insurgent's strategy. They are effective, provide safety and enable surprise attacks.

Second, commanders should not expect to hear about these tunnels. Even US units that had good relationships with local villages were often unaware of tunnel systems in their area of operations. The reasons are not always clear why this happened, though this fact alone should have given US intelligence officers pause. Intelligence support from the local population was not necessarily forthcoming.

Last, time is relevent in a counterinsurgency. If we assume it takes about 15 seconds for one NVA soldier to enter a tunnel with his gear, we can estimate it takes 25 minutes for a company of 100 troops to fully redeploy underground. This period of time is probably longer because the scenario assumes the NVA soldiers are all standing in line, waiting to go below, which they probably are not. Therefore, if a large enemy force is surround and appears to be fighting a delaying action, they may be trying to hold friendly forces at bay until the full unit has manged to enter their tunnels. If this unit then "disappears," commanders should move into the village and start searching for tunnel entrances. The blocking force was likely just buying time.

Tunnels and underground facilities remain a part of modern warfare and crime. They are present in the Middle East, along the DMZ in Korea and facilitate illegal cross-border activity around the world. They will remain a part of warfare because they are so effective. Commander should accordingly consider making their discovery a priority intelligence collection requirement. Their destruction and the denial of their use by guerilla forces takes away a valuable tool in their war effort.

For more information about the Vietnam War, see

(c) Thomas F. Pike, 2019