The Viet Cong and North Vietnamese for the most part didn’t have the powerful heavy weapons, helicopters, high-altitude bombers and tanks that the Americans had. They often made do with AK-47s semiautomatic guns, ingenious and deadly booby traps, and mines, often made from unexploded bombs harvested after American bombing missions. Some weapons such as tanks were of relatively little use in the mountains, swamps and rain forests where much of the fighting took place. The most useful—and often most advanced—heavy weaponry the North Vietnamese possessed were its Soviet-made anti-aircraft guns and artillery. In Moscow’s Museum of Armed Forces you can see a Kalashnikov used by a North Vietnamese soldier to kill 78 Americans on April 7, 1968.
Booby traps employed with deadly effectiveness by the North Vietnamese were often inspired by traps used to catch wild animals in the forest. They included neck snares that choke animal to death when it struggles to escape; spring snares that lift the animal in the air and hold it upside down; jaw traps that clamp down to the bone; falling weight traps that crush skulls; bamboo and wooden spike traps that skewer prey; hidden pits with spikes lying at the bottom; and pits with large spike-covered plates that enclosed on victim like a giant bear trap.
To hide their tracks some soldiers wore specially designed boots that left the imprint of Vietnamese-style sandals walking the opposite direction. When crossing roads North Vietnamese sometimes put down a canvas sheet over the roads, and the last man across would roll it up so there would be no prints
American soldiers used to use a dowsing-like device, made from L-shaped coat hangers to locate mines and booby traps. The U.S. Department of Interior even financed a study in which 150 people were asked to place wooden blocks over places where they got a positive dowsing reading. The pattern developed in which the participants had a tendency to put the rods where their magnetic field anomalies, which sometimes correspond with he presence of water and/or metal. [Source: People’s Almanac]