Every Japanese Sword Is a Katana
Japanese swords have evolved throughout Japanese history. That fact is entirely lost in popular culture, however, in which Japanese swords, regardless of design, are referred to as "katanas," because Katanas Are Just Better. In reality, the katana is a fairly recent weapon, relatively speaking, and hadn't been introduced yet during the classical period portrayed in many Jidai Geki films. That people in Japan sometimes use "katana" as a generic term for "sword", regardless of type, does not help to alleviate the confusion. Types of Japanese swords include:
- Tsurugi (剣): The oldest type of Japanese sword, this was essentially a copy of the Chinese jian. Straight-bladed and double-edged, it did not resemble a katana at all.
- Tachi (太刀): Large, curved sword similar to a katana, but longer and more deeply curved, and worn with the edge down. This was the katana-equivalent that was in use throughout most of the medieval period in Japan. Tachi are usually longer and more curved than katana, and also tempered harder than katana. This was somewhat an Achilles heel against the Mongols - the samurai complained their blades tended to chip against the Mongol armour.
- Katana (刀): Shorter and not as curved as the tachi, the katana was introduced in the Muromachi period (mostly analogous to the Sengoku-jidai) in response to weapons control regulations that restricted the length of swords that could be carried. Most tachi were shortened into katana in response to the new laws (rather unfortunately, since there were a lot of very famous tachi that got modified), and new swords produced during the period were made with less and different curvature to reflect their wearer's greater likelihood of drawing and using them on foot in a duel than from a horse on a battlefield. Worn with the cutting edge up. The uchigatana is the most common type of katana.
- Wakizashi (脇差): A Muromachi-period short sword, worn thrust sideways through the belt. (The name literally means "thrust sideways.") Sometimes worn together with a katana (this combination is called daishō, 大小) - this pair became the samurai's standard set of weapons during the Edo period, and was something of a status symbol. Their usage as such is actually much older, but only in Edo period it was strictly codified and actually enforced. Most samurai homes had a sword-rack near the door, so that visitors could leave their katana there but still have the wakizashi in case anything happened inside.
- Chiisagatana (小さ刀): A sword of intermediate length halfway between a katana and a wakizashi.
- Tantō (短刀): Basically a large dagger - generally mostly straight, and often rather wide. Was commonly worn with tachi as a part of an earlier form of the daishō, but diminished in popularity with the adoption of katana. In later eras they got stuck with the unfortunate name of harakirigatana, i.e. "the blade you use to cut your stomach open when committing seppuku".
- Ō-dachi (大太刀) and Nodachi (野太刀): Big honking swords larger than the norm. These swords were often so large that wielders had to wear them on their backs. (Kikuchiyo and Kamina were known to have wielded one.) They fell out of use with the field armies after proving themselves to be very expensive, uncomfortably heavy, and really difficult to make.
- Zanbato (斬馬刀): A BFS; essentially a humongous ō-dachi, roughly the size of a claymore. Like some of the more insane Zweihander designs, may never have been used in actual combat and made as more of a demonstration of iron forging prowess. Probably derived from the Chinese zhanmadao (as they both use the exact same characters), a sword that reputedly could cut through rider and horse at the same time; the name literally means "horse-executing sword".
- Nagamaki (長巻): Sword with a particularly long handle, roughly halfway between a sword and a polearm. Got their name (literally, "long winding") after the fact that their handles were usually simply wound with the cloth band, instead of the more elaborate woven patterns common for other Japanese swords.
- Daitō (大刀): A catchall word for the larger sword in a daishō pair. The word refers to the length of the blade, which was usually 70-90 cm.
- Shōtō (小刀) or Kodachi (小太刀): A catchall word for the shorter sword in a daishō pair. ("Kodachi" can also be used to refer to a blade that was similar to a wakizashi, but designed to be used by itself rather than in combination with a katana.)
- Ninjatō (忍者刀)/Ninjaken (忍者剣)/Shinobigatana (忍び刀): A fictional sword similar to the katana, depicted as being a ninja's version of the weapon. It is usually straight-bladed, has a square guard, and is shorter than katana. Often it can hold small weapons in the hilt. Sometimes it is explained that the blade is of lower quality than a samurai's swords and cheaper to make, so it was used by ninja. Again, it's fictional, and never actually existed. In reality, if a ninja used a sword (given that they were spies and assassins, knives were naturally more common), it would simply be whatever he could get his hands on.
- Bokken (木剣), or rather bokutō: A wooden sword used for training. It is typically modeled on the katana but can also be based on other swords, such as the wakizashi or the tantō. With the right training, it too was a deadly weapon (the legendary Miyamoto Musashi won his most famous duel with a bokken) and popular for ninja - after all, it's much easier (and cheaper!) to sneak a piece of wood around than sharp metal. A bokken is often designed to match the length and balance of the real sword, but to be heavier. The added weight helps build up muscle tone in the arms while training. Modern martial artists often use bokken made of even denser wood than was available to real samurai. Bokken is erroneous reading for the kanji; the correct reading is bokutō as the kanji 剣 is read tō at the end of words.
- Shinai (竹刀): Not really a sword, but a flexible shaft of tightly tied bamboo splints that represents one in kendo to avoid injury. Still can be extremely painful and can give a serious injury if used wrong, since the flexible splints can transfer energy better than a solid object under some conditions. Which is why kendo also involves wearing padded "armor".
- Dosu (ドス): A very short sword that looks more like a long knife. Easy to conceal, and traditionally carried by the Yakuza.
- Kyū Guntō: The old military sword, adopted by the Japanese military after the Meiji Restoration. Roughly resembles a Western-style sabre, but has a longer grip and balance closer to that of the katana, in order to make it easier to use for those officers familiar with Japanese weapons. Was later phased out in favor of the...
- Shin-guntō (新軍刀): Mass-produced officers' and NCOs' blades used from 1934 to the end of WWII. However, nationalists demanded that a more "native" sword be carried, so a design closely patterned on the katana was adopted. Needless to say, these were of much lower quality than most Japanese swords - while some Type 94 shin-guntō used traditionally made blades (particularly those carried by officers from the old samurai families, who would often place their ancestral blade into a Type 94 hilt), the Type 95 and 98 versions all used a blade that was essentially a piece of machined steel with an edge ground onto it.