Today let's take a look into the realm of Japanese swords. The very basics, like with all other cultures start with distinguishing them by length. They are the O-dachi, tachi, katana, wakizashi, and tanto.
O-dachi is an extremely long sword, like an oversized version of a regular sized katana. The blade length for these swords are usually around 70 inches long, and the overall length being about 105 inches long. These swords are also exceedingly rare to find, because of the large amount of materials needed to forge a sword and the extreme skill level required to properly make a sword of this size.
Pictured to the left is a genuine antique nihonto or Japanese made O-dachi, dating from the Kamakura period (1184-1332). Forged and signed by Taroumaru, this is an excellent example of an O-dachi that was possibly used in battle. This O-dachi sword is very heavy at 15.9lbs, and could only be wielded by a master swordsman. Sometimes, even two people had to wield such huge swords.
The curvature of the sword meant that it could be unsheathed more easily, especially while riding. The curvature is a product of the special heat treating process the Japanese have become so famous for. Differential clay hardening is an application of varying amounts of clay along the blade, thicker at the spine, and thinner along the edge. When heated to critical temperature, then quenched in water, this causes the metallic crystal structure within the sword to change. The edge is cooled very quickly and hardens into martensite, a very strong and brittle crystal structure, while the spine area cools slower and turns into pearlite which has flexible, and durable properties. These two crystal types meet along the blade and produce something called the hamon. Keep in mind that is isn't a forge welding line, but rather the transitional area between the pearlite crystals and martensite crystals. That hamon can be brought out and highlighted through polishing, and as can be seen in the tachi on the left, can be artistically executed.
Tachi were always worn with the edge facing downwards, and on the left side. At this time, Japanese culture did not acknowledge left handed users, therefore, everyone was either right handed, or learned right handed. After the introduction of the katana, tachi became symbols of rank and power, often worn for ceremonies and various rituals and could be extremely ornate in their furniture.
katana. Despite myths of its rumored sharpness, no they cannot cut through tanks and they are not unbreakable. They were the weapon of choice for samurai for hundreds of years due to their relative easier maneuverability compared to the tachi.
The katana is a shorter, less curved version of the tachi, and was created for foot soldiers. Since tachi were more curved and longer, they were not the easiest swords to use on foot. Many tachi were later shortened into katana length sizes, and still kept their characteristic koshi-sori or strong curvature towards the handle. Then swords started to be exclusively forged as katana, and usually featured a centered curvature, also known an tori-sori. Nowadays, almost all katana, both production and genuine nihonto, feature this style of curvature.
While the amount of curvature could vary, like with the tachi, the way of wearing the sword never did. Katana were worn with the edge facing upwards on the left side, and when a samurai was on official duty, he was required to wear a wakizashi short sword or tanto dagger together with the katana.
A wakizashi is a Japanese sword sword, and is a one-handed version of a katana, with roughly 18 inch blade length and about 23-25 inch overall length. As mentioned previously, samurai on official duty always wore the katana and a short sword together as a set, called a daisho. The wakizashi was the short sword of choice for many samurai, due to the fact that it could be used to devastating effect and could deal fatal blows fairly easily compared to a tanto dagger. However it is important to note that a tanto could also be worn as an acceptable short sword for a daisho set.
Wakizashi could also be used in hara-kiri or ritual suicide, but more
often than not, they were the backup weapon if the katana could not be
used, or in easily decapitating defeated enemies.
This is the last of the Japanese swords, the tanto. A tanto is a dagger-sized sword, of about 12 inches in length. Tanto in Japanese culture could be very highly regarded, as Masamune, one of the most famous Japanese sword smiths in history, specialized in forging tanto.
As mentioned before, the tanto could be worn as a companion sword to the katana. To clarify, a set of swords is called a daisho. The term daisho is derived from dai-to which refers to the katana, and sho-to which refers to the wakizashi OR tanto. Therefore a daisho would be comprised of a katana and wakizashi OR tanto.
Generally, tanto would be worn only by high ranking samurai, and the sho-to would always be worn closest to the body, generally with the hand guard in front of the navel, with the katana at an angle more or less perpendicular to the body, but can also be worn at a slight angle pointing inwards.
So we have covered the basics of the 5 basic types of Japanese swords based on length, the O-dachi, tachi, katana, wakizashi, and tanto. Armed with this knowledge, go ahead and buy swords that you think fits your taste and user preference.