[Justin Pasternak]

I know that their are prefixes such as Ko (small or old) or O (large or great) that are used for classifying japanese sword and dagger blades that are either shorter or longer than normal.

"For example a dagger (tanto) blade is usually under 1 shaku (11.93 inches or 30.3 cm) in length and a O-tanto (Long or Large Dagger) would be in excess of 1 shaku such as a dagger having a blade length of 1.173 Shaku or 14"."

And for a Katana blade (above 2 shaku in length) to be classified as an O-katana, is there any form of set length's such as for example having a blade longer than the average katana blade which is about 25" to 27"?

So, If I had a Katana blade of 30" inches would it be considered an O-Katana, since it is above the average blade length?

[Gabriel Lebec]

Hello Justin,

The "large" and "small" o- and ko- prefixes are often used by modern collectors as subjective adjective descriptors rather than strict academic classifications - they don't really separate weapons by function or cultural meaning very much. Some terms, like sunnobi tanto or kodachi, on the other hand, do separate by function and are therefore more meaningful, or else separate by mounting/provenance as in the case of tachi vs. katana (keep in mind tachi were usually longer than katana for functional reasons as well).

For a superb essay on exactly this topic, from which I shamelessly based most of that paragraph, please read Dr. Takeuchi's Historical Classification of Wakizashi and the Taxonomy of Nihonto Based on their Blade Length and Function/Purposes. Note that Dr. T mentions that during the Edo period, the "o-" and "ko-" classifications did in fact have official and specific meanings regarding wakizashi lengths.

In the case of katana, there's no real need for the o- designation; something longer would usually be made as a tachi, and something way longer would usually be made as or at least referred to as an odachi (commonly misnamed as "nodachi"). Traditional Japanese smiths don't really push these boundaries with regard to form; you're not likely to see something too difficult to classify as one of the above. Some nagamaki perhaps, and some martial arts call larger swords by other names (choken in the case of the Kage Ryu), but really they're all pretty similar.

A katana of 30"+ nagasa is usually just referred to as a "really long katana."

Another essay on the finer points of semantics and nihonto taxonomy, I encourage you to check out Dr T and Guido Schiller's article: The Mountings of the Japanese Sword. It actually goes quite beyond mountings in clarifying many of these points.

Cheers,
-Gabriel

[Ben C.]

[Gabriel Lebec]

Hi Ben,

Thanks for the extra detail on the language. One of the more annoying aspects of this hobby is how terms have shifted through multiple layers of meaning historically, not to mention the added complexity of the writing system and its multiple possible pronunciations/interpretations.

Cheers,
-GLL

[Justin Pasternak]

Thanks guys, for your help on the topic. This helped clear up alot of questions that I had.

Best Regards,

Justin

[Justin Pasternak]

This is probably a stupid question. I know that a Tachi with an extra long blade is referred to as an Odachi.

But, how long does the nagasa of the Tachi have to be to be classifyed as a Odachi?

From several sources that I've encountered across the net and books, it is said for a tachi to be classified as an Odachi it needs to have a Nagasa over 3 Shaku or 35.79 inches in length?

[Gabriel Lebec]

I am not aware of any hard rule, be it historic, modern, academic, legal, or whatever, for a blade to qualify as odachi. 3 shaku sounds like a solid guideline to me, since it lies near the upper end of the grey zone between exceptionally long tachi and relatively short odachi.