And since we brought up Japanese swords let me address this issue also (I'm a former fencer):
Japanese swords were technology advanced for their time, but they lacked the abilities that a European broadsword had.
The Japanese sword was sharpened the same way as a knife, at a 9 to 10 dgree angle. A European broadsword wsa sharpened at 60%, like a chisel because the broadsword was designed to blow through chainmail or breaking bones. I suspect many knights died of broken ribs rather than cuts.
The Japanese sword was esentially a large knife that was optimised for removing heads and would not have faired well at all against the broadsword.
The lack of a usable hilt on a Japanese sword has always bothered me until I figured out that the stiff leather and bamboo armor of the Samurai would protect them agains those swords. A broadsword would severe that armor as if weren't even present.
And if you want to compare light swords to Japanese swords the rapier was one of the most lethal weapons ever invented in the hands of cavalry office of the 17th century. Would have been no contest. Samurai down in under a minute.
As someone who has contested with all three (European "broadsword", Katana, and Rapier), I know better. It ain't the weapon, it's the circumstances and, foremost, the relative skill of the users.
The Mongol armor that the Japanese were encountering was made from boiled leather. When you put vegetable-tanned leather into very hot water (the ideal temp is actually 180F rather than boiling), it comes out very stretchy and flexible, but when it cools it becomes hard (but with a good amount of "give"). I've seen examples of this leather and it is like plastic.
Leather armor can take a cutting blow from a European-style sword, give a little, and bounce back. It is best defeated by a slicing blow from a very sharp sword
Chain mail, OTOH, is best defeated by a chopping blow from a blade that acts like a cold chisel
More like a razor. General rule of thumb: Utility knife angle is 19-21 degrees, axes, 45 or greater, and razors about 10. Then again, I can shave with a knife at 20 degrees--right off the block.
The steel and its treatment has a lot to do with how well the edge holds.
Interesting about finding carbon nanotubes in the steel. I can see how this contributed to the flexibility. Some specialty steel company, if they let the researchers go hog wild, might find a breakthrough--such as single grain on the edge with a carbon nanotube matrix in the bulk of the blade.
Just ruminating here. Don't mind me.)
Good article.