Japanese
定寸
Definition
The Tokugawa Shogunate standardized the size of swords in Japan during the Edo period to what is commonly called jōsun length. For katana jōsun is 2 shaku 3 sun 5 bu (71.21cm), for tantō - 8 sun 5 bu (25.76cm).
Tantō longer than jōsun are called sunnobi-tantō 寸延び短刀, and less than jōsun sunzumari-tantō 寸詰まり短刀. There was no standard length for wakizashi, but those over 1 shaku 8 Sun (54.5 cm) are called ō-wakizashi 大脇指. Tachi 太刀 of more than 3 Shaku (90.9 cm) are referred to as ōdachi 大太刀, whereas tachi under 2 shaku (60.6 cm) are called Kodachi 小太刀.
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