JAPANESE SWORD MEASUREMENT

SWORD BLADE MEASUREMENT

The blade length (nagasa) is measured in a straight line from the mune-machi (back blade notch) to the tip of the kissaki (point). The nakago is measured from the mune-machi to the tip of the nakago (nakago-jiri). The kissaki (point) is measured from the yokote to the tip of the kissaki. Sori (curvature)(see below) is measured from the back of the blade (mune) at the widest point on a straight line from the mune-machi to the tip of the kissaki (point).

** Japanese Unit Conversions **

1 shaku = 11.93 inches (30.30 cm)

1 shaku = 10 sun
1 sun = 1.193 inches (3.03 cm)

1 sun = 10 bu
1 bu = 0.119 inches (0.303 cm)

1 bu = 10 rin
1 rin = 0.01193 inches (0.0303 cm)

Note: 1 shaku is commonly approximated
to be 12 inches (1 foot)

SWORD BLADES CLASSIFIED BY LENGTH

Daito ( katana, uchi-katana, tachi, no-dachi ) - nagasa over 2 shaku
Shoto ( wakizashi, chisa-katana ) - nagasa between 1 and 2 shaku
Tanto - nagasa under 1 shaku

Some collectors add the descriptive prefixes "o-" or "ko-" to indicate a blade slightly longer than normal or somewhat shorter than normal; i.e., an "o-tanto" might have a blade slightly over 1 shaku in length, etc.

Blades with little or no curvature are termed "mu sori".
Some tanto may have a slight reversed inward curvature (uchi sori).