Originally Posted by Timo Nieminen
Shaka's successful imperialism wasn't the result of weapons - weapons rarely make the difference in war when neighbours fight each other. The credit should go to discipline and organisation (both on and off the battlefield).
Chaka's " successful imperialism" did, in fact, result from the modification of the throwing assegai into a stabbing Iklwa. It changed the entire tactic of the confrontation, allowing coordinated face-to-face contact and converting ritualistic hurling of solitary assegais from a distance with extremely low probability of any damage to the opponent into a dedicated mass murder.
In this he ( likely unknowingly) reproduced the Roman tactic: tightly organized legion moving inexorably forward and performing non-stop deathly stabbing.
Yes, stabbing spears were present in other African societies, but it was Chaka who conceptualized their use on a mass scale and integrated them into his vision of a novel military force dedicated to a total war.
In this Chaka was not alone: Mongols of Chingiz Khan devastated Russian and later East-Central European armies with new tactics based on the softening of the opposing force by rapid feighned cavalry assaults, false withdrawals, and tight communications between units. For that they used powerful bows and arrows and light sabers to slaughter disorganized and separated enemies. That was how Subedei and Jebe with 20,000 cavalrymen utterly annihilated 120,000-strong Russian army at Kalka river and, later on, the flower of European knighthood at Legnica.
And, yes, Ngombe/Ngulu beheading swords and the like could inflict damage, but they were not optimized for any stabbing or cutting function and, from the engineering point of view, their artistic/ ritualistic construction severely impaired their functional performance.
Every successful military requires a concept of the battle order and provision of the most appropriate weapons. Deliberately artistic configuration of the blades only gets in the way.
And you are correct: a conflict between neighbors does not require tactics and weapons optimized for killing. After all, each tribe will end up with its own territory and will continue to be autonomous. Former opponents will continue to co-exist. Things change when your goal is to acquire their territory and subjugate their population. This requires a lot of blood and gore. Chaka understood it.