The Vietcong used the complex Cu Chi tunnel system to withstand superior Allied firepower and launch attacks. During Operation Crimp, American and Australian forces faced significant tactical challenges from these hidden defences. The tunnels remained a vital stronghold until intensive aerial bombardments in 1969.
The Vietcong built tunnels during the war because they were fighting a much stronger enemy with aircraft, armoured vehicles, artillery and superior firepower.
Even when allied forces occupied the ground above them, the Vietcong used tunnels to:
- hide from allied patrols
- launch surprise attacks
- maintain control of local areas
- protect command networks
- store and move supplies.
Cu Chi tunnels
The most complex tunnel system was about 40 km from the South Vietnamese capital, Saigon (now Ho Chi Minh City), in the Cu Chi district. It was in an area known as the Iron Triangle, a Vietcong stronghold.
The tunnel system covered some 400 km to the north of the village of Củ Chi.
The Vietcong troops heavily defended the Cu Chi tunnels, using them as a base for attacks on Saigon.
The tunnels concealed living areas, storage depots, ordnance factories, hospitals and headquarters – a range of facilities that enabled people to live and wage war underground for years at a time.
Operation Crimp
When United States (US) and Australian troops started doing sweeps into the area during Operation Crimp, they had no idea the tunnels existed.
The allied operation involved some 8,000 troops from the US 1st Infantry Division and the 173rd Airborne Brigade, as well as troops from the 1st Battalion, Royal Australian Regiment (1RAR).
At the time, it was the largest Allied operation to defeat the Vietcong in the Cu Chi district.
The Vietcong troops were ready. They had been bombed and shelled, and they had seen reconnaissance aircraft overhead. They knew that such preparations were followed by an offensive.
The tunnels’ defenders were heavily outnumbered. Many of them were teenagers, and some were even younger. But in the kind of fighting for which they had been trained, these factors were not a disadvantage.
Space underground was limited, and a couple of men familiar with the tunnels’ layout could hold up a force and inflict casualties out of all proportion to their numbers.
The US and Australian troops had difficulty finding any enemy, but Vietcong snipers caused a steadily rising number of casualties.
As they moved through the Cu Chi district, the allied troops encountered mines, foxholes, trenches and caves, but made almost no Vietcong sightings.
There was little fighting of the type expected in a major offensive.
Even when it became apparent that the enemy was present in tunnels beneath their feet, they couldn't pursue the Vietcong without finding an entrance to the tunnels.
For the Australians, who had been dropped as a blocking force on Operation Crimp's northern perimeter, it was a frustrating experience.
By the third day, their area of responsibility had been covered, but no Vietcong had been killed or even seen. Only one conclusion could be reached: the enemy was underground.
As the Australians occupied the area, they began to find the tunnels.
Over the next 4 days, the allied troops uncovered nearly 2 km of Vietcong communication tunnels, bunkers and underground chambers in the Cu Chi area.
During their introduction to tunnel warfare, Australian troops found caches of ammunition, food and numerous booby traps. While they were developing systems to explore the tunnels during Operation Crimp, the Australians had yet to devise methods for engaging in underground combat.
By the time Operation Crimp ended on 14 January, the number of Australian war dead in South Vietnam had doubled from 8 to 16.
Behind them, the US and Australian troops left empty, burnt-out villages. Considered too close to the Vietcong, their populations had been relocated.
Operation Crimp showed that the Vietcong were a determined and well-organised enemy who could fight on their own terms, even during a major operation.
The existence and the extent of the tunnel systems surprised the allied forces.
One year after Operation Crimp, the Americans launched another offensive in the Cu Chi district, and even after this second series of attacks, the tunnels survived.
The Vietcong used their Cu Chi tunnels as a base to launch attacks on Saigon during the 1968 Tet Offensive. After the grievous casualties sustained by the Vietcong in Tet, the war against the US and its allies was carried more and more by the North Vietnamese Army, and the role of the tunnels diminished.
In 1969, carpet bombing by US aircraft rendered the tunnels uninhabitable.
Such was the rate of attrition among those who fought in the tunnels that of the 300 Vietcong engaged in their defence when Operation Crimp began, only 4 survived the war. By Vietnamese estimates, some 12,000 Vietcong and civilians lost their lives in Cu Chi during the war. The province has become a well-visited tourist destination because of the remnants of the wartime tunnels.
One of the 'Tunnel Rats', Lance Corporal Ron Rockliffe (5410234), 6th Battalion, The Royal Australian Regiment (6RAR), drops into a Vietcong tunnel during Operation Enoggera, South Vietnam, June 1966. The operation involved the search and destruction of a large tunnel network near the village of Long Phuoc. AWM CUN/66/0525/VN
