Bu (Shakkanho) (歩 (尺貫法))

Bu is a unit of length under the shakkanho (old Japanese system of weights and measures).

The unit originated in the Zhou Dynasty in China. Bu was body measurement and "one bu" was the length of two steps. It was later related to shaku and considered to be equal to the length of six or eight shaku. Six shaku (about 1.8 m) and eight shaku (about 2.4 m) are actually longer than the length of two steps, however, because bu was related to shaku at a time when a shaku was shorter than it is now. The unit of shaku became longer, so the unit of bu became longer.

The unit of length based on a step was used around the world, and pace (about 76cm) was used in English-speaking countries while Shuritt (71-75cm) was used in Germany. The unit of passus was used in ancient Rome and mile originated from mille passuum (thousandfold passus).

"Bu"also means a unit of area, one square bu (six shaku). Tsubo is also a unit of area in Japan and one tsubo is equal to one bu. "Bu" as a unit of area is detailed in an article "tsubo."

[Original Japanese]