There has been a nuclear war. There are now two sets of people: the barbarians and the scientists. The barbarians are distinguised by the type of weapons they are masters of, the rope/sword/short sticks etc. In the barbarian culture, they fight in a circle to sort out disagreements and arguments.
In one of the later books they are assaulting a mountain containing the scientists.
This is all I can remember.
Battle Circle by Piers Anthony, a trilogy consisting of Sos the Rope, Var the Stick, and Neq the Sword.
Wandering tribes of primitive humans meet and fight and love and die. When one tribe meets another, individuals fight inside a Battle Circle. The loser must become a member of the victorious tribe. Each warrior is named by his weapon. When Sol the Sword is bested by Sol of All Weapons, he loses his tribe, his name, and his weapon. Re-named Sos the Rope, he joins with Sol of All Weapons to try to create something greater than a world of Battle Circles
