[Timo Nieminen]

Originally Posted by ariel

In this he ( likely unknowingly) reproduced the Roman tactic: tightly organized legion moving inexorably forward and performing non-stop deathly stabbing.

As I said, discipline and organisation. Everybody in the region used shields and spears, and one can implement this same tactic with a multi-purpose throwing/thrusting spear (or with a variety of designs of thrusting spear). If Shaka's enemies had thought that the short thrusting spear was the key to his victories and adopted it (without the discipline and organisation), they would have lost just as badly, if not worse.

Originally Posted by ariel

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.

The sabre had been around for centuries. The composite bow had existed for over two millennia. Feigned withdrawals, and many of the other tactics the Mongols used were old and well-known steppe tactics. The elements of the Mongol military system that weren't just the usual steppe military system were largely adopted from the Khitans. There were no revolutionary changes or advances in weapons and tactics that enabled Mongol success.

Indeed, tactically the Mongols often only performed comparably with their enemies. Where they excelled was at the operational level, consistently fighting favourable battles, bypassing strongpoints, and achieving surprise. This achievement didn't depend on weapons, but on disciple and organisation. Part of that was good communications, which was achieved through existing technology (couriers on horseback) and organisation.

Originally Posted by ariel

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.

Consider the attached photos of two Congo swords. These are, IMO, quite typical Congo swords. Both show stereotypical design with prominent artistic elements. How do these artistic elements severely impair their performance? How is the function of the sickle sword in the OP severely impaired?

It's true that there are many African weapons that are purely ritual/ceremonial. In my experience, these are a small minority of the weapons, and in any case are militarily irrelevant since they're not fighting weapons.

Originally Posted by ariel

And you are correct: a conflict between neighbors does not require tactics and weapons optimized for killing.

You misunderstand. Neighbours (especially pre-industrial neighbours) are generally at similar levels of technology, and have access to the same or similar weapons. The main advantage of one neighbour over the other comes from organisation, numbers, or economics, not weapons.

Non-neighbours such as colonial European powers often had a major advantage due to weapons, which local powers could not always match due to their inability to manufacture similar weapons. An advantage in weapons, especially at the level of modern rifles vs muzzle-loader, bow, and spear, can make a difference (and was typically accompanied by an advantage in discipline and organisation, which made things even worse). Weapons can make a difference. Menelik II was wise to buy modern rifles as quickly as he could.