The Japanese Sword
What generally differentiates the different swords is their length. Japanese swords are measured in units of shaku (one shaku is approximately equivalent to 30 cm or one foot). A blade shorter than one shaku is considered a tantō (knife). A blade longer than one shaku but less than two is considered a shōtō (short sword). The wakizashi and kodachi are in this category.
A blade longer than two shaku is considered a daitō, or long sword. Before 1500 most swords were usually worn suspended from cords on a belt, edge-down. This style is called jindachi-zukuri, and daitō worn in this fashion are called tachi (average blade length of 75-80 cm). From 1600 to 1867, more swords were worn through an obi (sash), paired with a smaller blade; both worn edge-up. This style is called buke-zukuri, and all daitō worn in this fashion are katana, averaging 70-74 cm (2 shaku 3 sun to 2 shaku 4 sun 5 bu) in blade length. However, nihontō of longer lengths also existed, including lengths up to 78 cm (2 shaku 5 sun 5 bu). The weight of a nihontō rarely exceeded 1 kg without the saya.
A chisakatana is simply a shorter nihontō. It is longer than the wakizashi, lying between one and two shaku in length. The most common reference to a chiisakatana is a shorter nihontō that does not have a companion blade. They were most commonly made in the buke-zukuri mounting.
Abnormally long blades (longer than 3 shaku), usually carried across the back, are called ōdachi or nodachi. The word ōdachi is also sometimes used as a synonym for nihontō. Odachi means "Great Sword", and Nodachi translates to "Field sword". Nodachi were used during war as the longer sword gave a foot soldier a reach advantage, but now the nodachi are illegal because of its effectiveness as a killing weapon. Citizens are not allowed to possess an odachi unless it is for ceremonial purposes.
Here is a list of lengths for different types of swords:
- Nodachi, Ōdachi, Jin tachi: 90cm and over.
- Tachi, Katana: over 60,6 cm (more than two shaku)
- Wakizashi: between 30,3 cm - 60,6 cm (between one and two shaku)
- Tantō, Aikuchi: under 30,3 cm (under one shaku)
Swords whose length is next to a different classification type are described with a prefix 'O-' (for great) or 'Ko-' (for small), e.g. a Wakizashi with a length of 59 cm is called a O-wakizashi (almost a Katana) whereas a Katana with 61 cm is called a Ko-Katana (for small Katana) .
Since 1867, restrictions and/or the deconstruction of the samurai class meant that most blades have been worn jindachi-zukuri style, like Western navy officers. Recently (since 1953) there has been a resurgence in the buke-zukuri style, permitted only for demonstration purposes. Swords designed specifically to be tachi are generally kotō rather than shintō, so they are generally better manufactured and more elaborately decorated. However, these are still katana if worn in modern buke-zukuri style.
Most old Japanese swords can be traced back to one of five provinces, each of which had its own school, traditions and "trademarks" (e.g., the swords from Mino province were "from the start famous for their sharpness"). These schools are known as Gokaden (The Five Traditions). These traditions and provinces are as follows:
- Sōshū School, known for itame hada and midareba hamon in nie deki.
- Yamato School, known for masame hada and suguha hamon in nie deki.
- Bizen School, known for mokume hada and midareba hamon in nioi deki.
- Yamashiro School, known for mokume hada and suguha hamon in nei deki.
- Mino School, known for hard mokume hada and midareba mixed with togari-ba.
In the Kotō era there were several other schools that did not fit within the Gokaden or were known to mix elements of each Gokaden, and they were called wakimono (small school). There were 19 commonly referenced wakimono.
