A really good sword

[DangerousThing]

Originally Posted by Willy

Cutting through armor sounds nice, but wouldn´t work. The typical japanese and medieval european blades where formed different for a reason. Japanese armor was seldom made complete of metall, at least no full plate, so the curve allowed a cut like a saber doing more damage like a saber to weakly protected flesh.

The japanes katana and similar blades were curved because of metallurgy. They had few sources of good iron for steel, so they used a separate piece of metal for the edge of the blade and forged the two together. Then they put clay around the blade for hardening it, with less clay for the edge. This produced a curve in the blade.

The blade was also softer on the back than the edge.

I am sure that the samurai studied the blades and developed techniques to used the strengths of the blade and avoid the weaknesses.

[DanHoward]

Originally Posted by DangerousThing

The japanes katana and similar blades were curved because of metallurgy. They had few sources of good iron for steel, so they used a separate piece of metal for the edge of the blade and forged the two together. Then they put clay around the blade for hardening it, with less clay for the edge. This produced a curve in the blade.

That was just one way that they made swords and may not have been the most common way. Some were made from all medium-carbon steel and differentially heat treated. Some were made with a high-carbon steel edge forge-welded onto a softer core but not heat-treated. Some were made from low carbon steel with work-hardened edges but no heat treatment. Regardless of how they were made, they all had similar curves.

[Anthony]

Originally Posted by DangerousThing

The japanes katana and similar blades were curved because of metallurgy.

Had there been a reason to make a straight blade, they could have made straight blades -- I'm sure that some time since 500BC Chinese Jian techniques could have made their way into Japan (I assume the Chinese made straight swords for the same reason the Europeans did; they weren't metal poor like Japan so iron armor was reasonably common).

[DanHoward]

Originally Posted by Anthony

Had there been a reason to make a straight blade, they could have made straight blades -- I'm sure that some time since 500BC Chinese Jian techniques could have made their way into Japan

Japanese single-edged straight swords were called chokutō and were common before the 9th C. They were made using the same techniques that they used for later curved swords.

[(E)]

More modern versions of the sharpness tests that I have heard of are blowing on a hank of wool to test whether the (hand) shears are sharp enough.

Similarly an axe blade can be similarly sharpened to the point where it can take the hair off your arm, the point there would be to cut more wood fibers with the same amount of swing effort.

This is a link to a video about the Wilkinson Sword factory (1965) the blade test is interesting.

[Willy]

Yes, Japan had historically less access to good iron than other nation, but at some point they found out, that a curved blade does more damage to lightly protetected bodies. Making contact with foreigners, a valued trade good was high quality steel, and techniques to forge it. Also of course helmets cuirass and other steel equipment. there are nice drawings showing samurai at mass before battle, wearing cuirass, morion helmet alongside with traditional clothes and a katana. Some historians claim that the typical japanese armor was invented because of the lack of enough good iron to fit out large troops.

European military blades have been straight for a long time, the moment armor was reduced the became more and more curved. From the first black powder weapons to the WWII, you can see a change in the form and weight of the blade.

[Varyon]

Originally Posted by Joe

What about so-called "slices" against flesh?

Relevant thread. As noted there, any difference at GURPS resolution would be cinematic in nature.

[DanHoward]

Originally Posted by Willy

Yes, Japan had historically less access to good iron than other nation, but at some point they found out, that a curved blade does more damage to lightly protetected bodies.

Only against a flat surface and humans are not flat. There have been numerous experiments proving that, in the real world, there is no noticeable difference between a curved and straight blade when cutting. They just require different techniques. The techniques that work best with curved swords are generally more useful from horseback. Samurai continued to carry curved swords when they stopped being cavalry because of fashion and tradition, not because they were better at cutting.

This is worth reading.
http://www.thearma.org/spotlight/GTA...d_impacts3.htm

Some historians claim that the typical japanese armor was invented because of the lack of enough good iron to fit out large troops.

They would be wrong. Lamellar was the most popular type of armour all throughout Asia - even in regions that had very good reserves of iron. And Japanese armour was not invented by the Japanese. It was imported from the continent and adapted for local use. Pretty much all Japanese military technology originated on the continent. Militarily, for most of its history, Japan was retarded* when compared to continental Asian cultures. Most innovations came from abroad.


* the original definition of the word, not the modern pejorative.

[Jinumon]

Originally Posted by Willy

Yes, Japan had historically less access to good iron than other nation, but at some point they found out, that a curved blade does more damage to lightly protetected bodies. Making contact with foreigners, a valued trade good was high quality steel, and techniques to forge it. Also of course helmets cuirass and other steel equipment. there are nice drawings showing samurai at mass before battle, wearing cuirass, morion helmet alongside with traditional clothes and a katana. Some historians claim that the typical japanese armor was invented because of the lack of enough good iron to fit out large troops.

From my understanding (which is, admittedly, limited) the classic curve in a katana/tachi is the result of differential hardening techniques and the use of water (instead of oil) during the quenching process. The katana/tachi originally came to be when Japanese smiths attempted to recreate the Chinese tang dao that appeared in Japan (along with many things that would become Japanese cultural mainstays like) during China's Tang Dynasty, which exerted heavy cultural influence on Japan and Korea. The curve is an accident, more or less.

Additionally, while there is some evidence to support that heavily curved swords may have additional cutting power due to a drastically increased cutting ratio, the factor by which the very minor curve of a katana or tachi increases its cutting ratio is essentially negligible. The "legendary" reputation of the katana's cutting power against soft targets (which is often overstated) is more due to it's construction. The soft metal of the spine and habaki help to absorb shock and prevent surface skidding due to poor edge alignment, and the high-carbon, water-quenched steel of the edge borders on tool steel in its hardness, allowing it to hold an incredibly sharp edge (at the trade-off of being brittle and prone to chipping).

Jinumon

[DanHoward]

Originally Posted by Jinumon

From my understanding (which is, admittedly, limited) the classic curve in a katana/tachi is the result of differential hardening techniques and the use of water (instead of oil) during the quenching process. The katana/tachi originally came to be when Japanese smiths attempted to recreate the Chinese tang dao that appeared in Japan (along with many things that would become Japanese cultural mainstays like) during China's Tang Dynasty, which exerted heavy cultural influence on Japan and Korea. The curve is an accident, more or less.

We've already shown that this is a load of bollocks. They had single-edged straight swords before the 9th century that were differentially hardened and there are plenty of curved Japanese swords that were not differentially hardened.

Additionally, while there is some evidence to support that heavily curved swords may have additional cutting power due to a drastically increased cutting ratio.

Only against a flat surface. Humans are not flat.

The soft metal of the spine and habaki help to absorb shock and prevent surface skidding due to poor edge alignment, and the high-carbon, water-quenched steel of the edge borders on tool steel in its hardness, allowing it to hold an incredibly sharp edge (at the trade-off of being brittle and prone to chipping).

Only some Japanese swords were made like this and probably not the majority of them.