The ambush is a favoured tactic of insurgents. Counter-insurgent forces are usually better equipped and often better trained than the insurgents they seek to destroy. They also tend to enjoy the benefits of high firepower and mobility we outlined in chapter 1. To redress this imbalance, insurgents often seek to employ the ambush. It allows them to select and prepare the ground in advance of the contact and to achieve surprise, both of which should contribute to better combat outcomes for them.

Like the later VC/PAVN, the Viet Minh were skilled practitioners of the ambush. One of their most spectacular successes was the destruction of Groupement Mobile 100 in June and July 1954, days before a ceasefire that presaged the 1 August armistice and the end of French control of Indo-china. Groupement Mobile 100 was a mobile force of three infantry battalions with artillery and tank support. It had been ordered to withdraw from its defensive positions at An Khe to Pleiku, a distance of 80 kilometres via Route Coloniale 19. It was ambushed repeatedly as it withdrew. Its three infantry battalions lost almost half their strength in casualties, the artillery lost more than half its men and all its guns. Large numbers of vehicles, communications equipment and weapons were either destroyed or captured by the Viet Minh.

The fate of Groupement Mobile 100 demonstrated how lightly armed insurgents without the advantages of tanks, artillery, sophisticated radio communications, air power and motor vehicles could exploit the ambush to devastating effect. It also demonstrated that the Viet Minh and later the VC/ PAVN conceived of the ambush on a grand scale. It could be an intimate tactical technique involving a few men lying in wait on a jungle track, but it could also be employed, as it was against Groupement Mobile 100, on a regimental scale to achieve the annihilation of large and capable enemy forces.

The Australian Army possibly had the fate of Groupement Mobile 100 in mind when it noted in its doctrinal pamphlet, The Enemy 1964, that the ambush was the ‘most widely used insurgent technique. In the Indo-China war it was used to perfection and the French were unable to find an effective counter to it. As a result, towards the end they were denied the use of many roads. When they did use roads they took calculated risks and often lost whole battalions in large ambushes.’