Editing Japanese sword (section)

=== Length ===
[[File:朱漆大小, Daishō.jpg|thumb|300px|Two antique ''koshirae'', ''[[katana]]'' (top), ''[[wakizashi]]'' (bottom), in the form of a ''[[daishō]]'' (matched set). 19th century, [[Edo period]]. [[Tokyo National Museum]].]]
[[File:Norishige.jpg|thumb|''Tachi'' by ''Norishige'' ca. 1300 CE, made ''ō-suriage'' (greatly shortened) during the [[Edo period]] for use as a "katana" by cutting off the original tang and reforming it higher up the cutting edge.]]
What generally differentiates the different swords is their length. Japanese swords are measured in units of ''[[Shaku (unit)|shaku]]''. Since 1891, the modern Japanese shaku is approximately equal to a foot (11.93&nbsp;inches), calibrated with the meter to equal exactly 10 meters per 33 shaku (30.30&nbsp;cm).

However, the historical shaku was slightly longer (13.96&nbsp;inches or 35.45&nbsp;cm). Thus, there may sometimes be confusion about the blade lengths, depending on which shaku value is being assumed when converting to metric or U.S. customary measurements.

The three main divisions of Japanese blade length are:
* Less than 1 ''shaku'' for ''[[tantō]]'' ([[knife]] or [[dagger]]).
* Between 1 and 2 ''shaku'' for {{Nihongo|''shōtō''|小刀:しょうとう}} (''[[wakizashi]]'' or ''[[kodachi]]'').
* Greater than 2 ''shaku'' for {{Nihongo|''daitō''|大刀}} (long sword, such as ''[[katana]]'' or ''[[tachi]]'').

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. The length is measured in a straight line across the back of the blade from tip to ''munemachi'' (where blade meets [[Tang (tools)|tang]]). Most blades that fall into the ''"shōtō"'' size range are ''[[wakizashi]]''. However, some ''daitō'' were designed with blades slightly shorter than 2 ''shaku''. These were called ''[[kodachi]]'' and are somewhere in between a true ''daitō'' and a ''wakizashi''. A ''shōtō'' and a ''daitō'' together are called a ''[[daishō]]'' (literally, "big-little"<ref name="books.google.com">[https://books.google.com/books?id=vFS2iT8QjqEC&pg=PA68 ''The Japanese sword'', Kanzan Satō, Kodansha International, 1983 p.68]</ref>). The ''daishō'' was the symbolic armament of the [[Edo period]] [[samurai]].

A blade longer than two ''shaku'' is considered a ''daitō'', or long sword. To qualify as a ''daitō'' the sword must have a blade longer than 2 ''shaku'' (approximately 24&nbsp;inches or 60 centimeters) in a straight line. While there is a well defined lower limit to the length of a ''daitō'', the upper limit is not well enforced; a number of modern historians, swordsmiths, etc. say that swords that are over 3 ''shaku'' in blade length are "longer than normal ''daitō''" and are usually referred to as ''[[ōdachi]]''.{{Citation needed|date=August 2015}} The word ''"daitō"'' is often used when explaining the related terms ''shōtō'' (short sword) and ''daishō'' (the set of both large and small sword). [[Miyamoto Musashi]] refers to the long sword in ''The Book of Five Rings''. He is referring to the ''katana'' in this, and refers to the ''nodachi'' and the ''odachi'' as "extra-long swords".

Before about 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&nbsp;cm).<ref name="Gilbertson">{{cite book| last = Gilbertson| first =E.|author2=Kowaki, G. | title = The Genealogy of the Miochin Family: Armourers, Sword- smiths and Artists in Iron, Twelfth to the Eighteenth Century| publisher = Transactions and Proceedings of the Japan Society| year = 1892| location =London  }}</ref> From 1600 to 1867, more swords were worn through an ''[[obi (sash)|obi]]'' (sash), paired with a smaller blade; both worn edge-up.<ref name="WBAR">{{cite book | last = Ratti| first = Oscar |author2=Adele Westbrook| title = Secrets of the Samurai: The Martial Arts of Feudal Japan| publisher = Tuttle Publishing| year = 1991| page = 484| isbn = 978-0-8048-1684-7  }}</ref> This style is called ''buke-zukuri'', and all ''daitō'' worn in this fashion are ''katana'', averaging 70–74&nbsp;cm (2 shaku 3 sun to 2 shaku 4 sun 5 bu) in blade length. However, Japanese swords of longer lengths also existed, including lengths up to 78&nbsp;cm (2 shaku 5 sun 5 bu).

It was not simply that the swords were worn by cords on a belt, as a 'style' of sorts. Such a statement trivializes an important function of such a manner of bearing the sword.<ref>{{Cite web |last=Olivier |date=2024-01-05 |title=Japan: Wakizashi, Tachi, and Katana, the Samurai Heritage |url=https://www.olivierrobert.net/post/japan-wakizashi-tachi-and-katana-the-samurai-heritage |access-date=2025-04-05 |website=olivierrobert.net |language=en}}</ref> It was a very direct example of 'form following function.' At this point in Japanese history, much of the warfare was fought on horseback. Being so, if the sword or blade were in a more vertical position, it would be cumbersome, and awkward to draw. Suspending the sword by 'cords' allowed the sheath to be more horizontal, and far less likely to bind while drawing it in that position.<ref>{{Cite web |date=2023-03-23 |title=Why is katana wear and display with edge upward, Learn the reasons |url=https://romanceofmen.com/blogs/katana-info/why-is-katana-wear-and-display-with-edge-upward |access-date=2025-04-05 |website=Romance of Men}}</ref>

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 Japanese swords. ''Odachi'' means "great sword", and ''Nodachi'' translates to "field sword". These greatswords were used during war, as the longer sword gave a foot soldier a reach advantage. These swords are now illegal<ref>{{cite book |url=http://www.bushidojapaneseswords.com/SwordLawLetter.pdf |title=The Japanese Sword Law & Export/Import of Swords Into/Out of Japan |first=Guido |last=Schiller |access-date=2011-07-20 |archive-url=https://web.archive.org/web/20110929172018/http://www.bushidojapaneseswords.com/SwordLawLetter.pdf |archive-date=2011-09-29 |url-status=dead }}</ref> in Japan. Citizens are not allowed to possess an ''odachi'' unless it is for ceremonial purposes.

Here is a list of lengths for different types of blades:<ref>{{cite book | last = Stone | first = George Cameron | author-link = George Cameron Stone | title = A Glossary of the Construction, Decoration, and Use of Arms and Armor in All Countries and in All Times | orig-year = 1934 | year = 1999 | publisher = Dover Publications | location = Mineola NY | isbn = 0-486-40726-8 | page = 314| title-link = A Glossary of the Construction, Decoration, and Use of Arms and Armor in All Countries and in All Times }}</ref>
* [[Nodachi]], [[Ōdachi]], [[Jin tachi]]: 90.9&nbsp;cm and over (more than three shaku)
* [[Tachi]], [[Katana]]: over 60.6&nbsp;cm (more than two shaku)
* [[Wakizashi]]: between 30.3 and 60.6&nbsp;cm (between one and two shaku)
* [[Tantō]], [[Aikuchi]]: under 30.3&nbsp;cm (less than one shaku)

Blades 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&nbsp;cm is called an O-wakizashi (almost a Katana) whereas a Katana of 61&nbsp;cm is called a Ko-Katana (for small Katana; but note that a small accessory blade sometimes found in the sheath of a long sword is also a "kogatana" (小刀)<ref name="Suenaga 1975"/>).

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. Since 1953, there has been a resurgence in the ''buke-zukuri'' style, permitted only for demonstration purposes.