Tuesday, May 22, 2007

Shakkan-Ho Conversions to Metric and Imperial Systems

A useful utility to convert between old Japanese units (Shakkan-Ho) and the good old Metric and Imperial Systems.

Shakkan-Ho Metric System Imperial System
shaku (尺)
sun (寸)
bu (分)
  cm  inch

One shaku (尺) is approximately 30cm. One sun (寸) is about 3cm, while one bu (分) equals 3mm. As a curiosity, one ken is equivalent to 6 shaku (180cm), approximately the height of a man.

Even when Shakkan-Ho is the old system, it's still used in Japanese martial arts for measuring the length of weapons, as well as for clothing (in which case a bu corresponds to 3.79mm) and footwear (when it corresponds to 2.4mm.) In any case, one shaku always equals to ten sun; and one sun contains always ten bu.

Thanks to Leonard from www.network54.com forums and to Kampai Budokai for the good information and the JavaScript code.