Hype . . .
Hype is part of the American scene, maybe even the culture, and most of us have learned this and are ready to discount a lot of hype we hear. In some areas, however, it appears that hype is becoming true, and many people take as facts stories that are, at best, outrageous. This seems to be particularly true with the Japanese sword. In the early 1950s, with the release of the movie Bad Day at Black Rock, in which one-armed Spencer Tracy uses karate/judo to tear up villain Ernest Borgnine, the U.S. went on a kick glorifying the Oriental martial arts. Since that time we have been treated to increasingly impossible feats of derring-do -- heroes who leap straight up over 10 feet, who unarmed and single-handedly take 15-20 villains and destroy them without working up a sweat or getting a bloody nose, who can hurl a knife 50 feet into the trigger guard of a pistol. Ridiculous.
As a student of arms and armor for many years, I find this both distressing and amusing. When I mention that a Viking sword, "Quernbiter" by name, was called this because it was supposed to have cut a millstone in half, everyone laughs and considers it a tall tale, which it undoubtedly was. Then the same audience will gravely assure me that the Japanese Katana has been known to cut a machine gun barrel in half.
This stunt must have happened several times, because when I tried to track the source, it seems to have occurred on Guadalcanal, Bougainville, Iwo Jima, Tarawa, and several other islands. I have to believe Japanese soldiers have some sort of pathological hatred for machine gun barrels. I have also wondered why they never tried to cut down the gunner.
Not only are Japanese blades exalted by such folks to the point of sheer absurdity, but European blades are downgraded until they become mere bars of iron, incapable of cutting hot butter. This just isn't true.
Students of arms and armor have always regarded the Japanese sword as a very fine weapon. It has good balance, may be well constructed, and it does what it was designed to do pretty well. But it is made out of steel, and has all the limitations of other steel swords. It isn't magic.
The earliest Japanese swords were direct descendents of the Chinese swords of the same period-straight, single-edged blades. These swords were poorly made, and may not have been tempered. Around 300 to 400 AD the Japanese learned how to temper the swords to produce a steely iron. Even after this, the sword was not highly regarded, and the bow was considered much superior. Soon, straight double-edged swords began to appear, but did not remain on the scene very long, possibly because tempering a double-edged sword offers problems. Legend has it that a single smith, Amakuni, designed the first single-edged and curved sword. The exact shape of this blade is not known, but it was not until roughly 1100 AD that the sword reached the final shape. By 1300, it was a truly good sword and very well made. These early blades all seemed to be slightly larger and longer than blades made after the end of the 16th century. There have been volumes written on the methods of constructing a Japanese sword, and it is not my purpose here to elaborate on them. The method was complex and involved layering the steel to produce a blade very nearly homogenous in its various elements. On top of this, a very hard steel was used for the edge, and a softer, more shock resistant type was used for the rest of the blade. Sometimes the edge was covered by the softer metal, sometimes the hard steel covered a softer body.
As early as 700 BC, the Celts were forging weapons, both spears and swords, by piling on layers of iron and forging the whole mess. This process continually improved until by 500 AD excellent pattern-welded swords were being made. In this process, bundles of carburized iron bars were welded together, and then a hard steel edge was welded on. This produced a sword, usually double-edged, with a soft, resilient body and a hard edge. The sword was flat, rather thin, quite light and flexible. Weight was in the area of 28 to 40 ounces.
These swords remained quite popular until about 900 AD when a new sword appeared. This sword was somewhat slimmer in the area of the point, tapering more sharply from the hilt, and was composed of steel-not iron that had been carburized, but steel all the way through. They were easier to make and, for all intents and purposes, just as strong as the earlier blades.
Two very important factors should be noted here. The European smiths were constantly trying out slight variations and whole new shapes. There were single-edged swords, slightly curved blades, and short swords like the Roman gladius as well as wide-bladed chopping weapons.
The Japanese, once they had decided on a basic shape, never made any attempts to improve on it. Many would like to say that having found the perfect shape, there was no reason to improve on it. I don't think that's true at all.
The Japanese culture has always been quite rigid, heavily bound by tradition. This highly controlled society did not encourage experimentation. The plus side is that it did leave us with a large number of very fine swords that are quite old and in excellent shape.
The Japanese sword is a superb draw-cutting weapon. This is the method that has been taught for the past several hundred years, and the evidence seems to indicate that it was always used in a similar fashion. In a draw cut, the blade is pulled as it cuts, and therefore not only shears, but slices as well. In soft tissue such as flesh or bone, it delivers a truly fearsome cut, being easily capable of cutting a torso in half. The draw back is that it doesn't cut armor, even mail, very well. A draw cut is very ineffective against hard armor. Changing the cut, and delivering a shearing blow does not work either. The blade of the katana is thick, with a sharp cutting bevel. The edge is strong, but the wedge it presents has to move aside more material. When cutting into metal, this is very difficult to do.
There are two additional points that should be considered. The Japanese sword was a two-handed weapon. Using both hands, a much harder blow can be delivered. Earlier swords, which were slightly heavier and longer, would add even additional force to the blow. But even with these advantages, the sword was not very good at penetrating armor.
The Japanese made good swords, but they also made very good armor. Many of the suits have plates of the same steel as the sword blades. The front of the plates was just as hard as the sword edge, while the back was soft and springy.
In order to have a good chance against the armor there are three weapons that are much better than the sword. They are the bow, the yari (spear) and the naginata. That explains why in battle, the three principal weapons used were the bow, the yari and the naginata.
In Europe, when practical firearms made armor obsolete, it was quickly abandoned. The same thing is true of Japan. One thing the Japanese are not is stupid.
All of the above refers to fully armored warriors. Never forget that in both Europe and Japan there were many warriors on the field who were not fully armored.
Another "fact" about Japanese swords is that the point, which is distinct and unique, is an armor-piercing point. It isn't. Shoving a knife or sword through a car door isn't that hard and many blades can do it. The Japanese point is harder to pierce with than many other designs. However that point is one of the best cutting points ever designed. Generally a sword point involved in a cut produces a lot of drag and reduces the efficiency of the cut. However, the Japanese point with its sharply angled "edge" portion, actually aids the cut. This would be quite important, as many standard cuts with Japanese swords are made with the first 6 inches of the blade. Europeans simply ignored the problem, which for them was very minor. Most of their cuts were made well back of the point. Due to the shape of the sword, the optimal striking point on most European blades was very well down the blade. Much later, many European cavalry sabers had points similar to the Japanese.
I have been assured, frequently in fact, that Japanese blades are so strong and tough that they never break, nick or bend. Well, they break, they nick, and they bend. They frequently nick quite badly. Damascus steel is a superior steel, or it can be when done by a superb smith. But even a superior steel is still steel and will respond like steel. One sad fact is that the harder the steel, the more likely it is to chip and nick. A softer metal will bend, flatten or otherwise distort. When this happens, it is relatively easy to pound or file a new cutting edge. When a chip leaves a gap, not much can be done. A piece can be reforged into the blade, but this also requires that the blade be retempered.