The Japanese (Shakkanhō) Unit Conversion Calculator contains a series of functions designed to convert Japanese measurements from the Shakkanhō system to modern (Western), metric and imperial units.

The Math / Science

The Shakkanhō is a traditional system of units and measurements used in Japan historically and in some instances during the present day. It is based on Chinese units of measurements (C. shìzhì ). The values of units in comparison to the metric system were set in 1891, but historically varied based on locality and time period.

This calculator allows users to convert Japanese measurements (based on their 1891 conversions) to their Western, imperial and metric counterparts. The calculator contains four equations listed alphabetically in order to calculate standard measurements such as area and length. Following this is an additional equation used to calculate the weight of rice.

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Japanese (Shakkanho) Unit Conversion Calculators

• Japanese Area - Shaku(勺), Go(合), Jo(畳), Tsubo(坪), Bu(歩), Se(畝), Tan (段 or 反), and Chō or Chōbu (町 and 町歩).
• Japanese Lengths - Mō (毛 or 毫), Rin (厘), Bu (分), Sun (寸), Shaku (尺), Ken (間), Hiro (?), Jō (丈), Chō (町), and Ri (里).
• Japanese Volume (Dry and Liquid) - Sai (才), Shaku (勺), Gō (合), Shō (升), To (斗), and Koku (石).
• Japanese Weight and Mass - Mō (毛 or 毫), Rin (厘), Bu (分), Monme or Momme (匁), Ryō (両), Hyakume (百目), Kin (斤), Kan or Kanme (貫 and 貫目), Maru (丸), and Tan (担 or 擔).
• Japanese Rice Weights - Shaku (勺), Gō (合), Shō (升), To (斗), Hyō (俵), and Koku (石).

Japanese Units and Metric Equivalences
Japanese Area Units Shaku (勺) = 330.6cm2 Gō (合) = 0.3306m2 Jō (畳) = 1.653m2 Tsubo (坪) or Bu (歩) =3.306m2 Se (畝) = 99.17m2 Tan (段 or 反) = 991.7m2 Chō or Chōbu (町 and 町歩) = 9917m2	Japanese Length Units Mō (毛 or 毫) = 0.03030mm Rin (厘) = 0.3030mm Bu (分) = 3.030mm Sun (寸) = 3.030cm Shaku (尺) = 30.30cm Ken (間) = 1.818m Jō (丈) = 3.030m Chō (町) = 109.09m Ri (里) = 3.927km
Japanese Volume Units Sai (才) = 1.804mL Shaku (勺) = 18.04mL Gō (合) = 180.4mL Shō (升) = 1.804L To (斗) = 18.04L Koku (石) = 180.4L	Japanese Weight and Mass Units Mō (毛 or 毫) = 3.75mg Rin (厘) = 37.5mg Bu (分) = 375mg Monme or Momme (匁) = 3.75g Ryō (両) = 37.5g Hyakume (百目) = 375g Kin (斤) = 600g Kan or Kanme (貫 and 貫目) = 3.75kg Maru (丸) = 30kg Tan (担 or 擔) = 60kg
Japanese Rice Measurements Shaku (勺) = 15g Gō (合) = 150g Shō (升) = 1.5kg To (斗) = 15kg Hyō (俵) = 60kg Koku (石) = 150kg	Japanese Currency Yen per Dollar: ¥154.72 JPY = $1.0 USD Yen per Liter to Dollars per Gallon Yen per Kilogram to Dollars per Pound

Instructions

Firstly, select a category on the calculator, e.g. Japanese (Shakkanhō) Lengths. Secondly, select the unit that you wish to convert from the drop-down menu. Following your selection, enter the value of the unit in numerical form.  The calculator will then convert this value to a Western unit (in the case of Mō to millimetres). Finally, you have the option to use a second drop-down menu (adjacent to the calculator's answer) in order to automatically convert the answer to other Western units of measurement, e.g. inches.

Further Notes

The individual pages for the constants and equations used in this calculator provide further details regarding Shakkanhō units, for example, alternative naming conventions. Inspiration from the algorithms of other vCalc calculators, constants, and equations were drawn upon when creating this calculator, its equations and constants. Of particular interest was the Bible Calculator which can be viewed here.