Japanese Scale Rule

This heavy brass ruler is divided to millimeters along one edge. The other edge is divided into ten units of 1-3/16" (3 cm). Each unit is thus roughly equivalent to the sun, a traditional Japanese unit of length that is 1/10 of a shaku. Two of the units are subdivided into 50 parts; the other eight are subdivided into 20 parts. Neither of the scales are sequentially numbered. Instead, the units of each scale are marked with a small "0," with an additional three zeroes above the "0" at the center of the scale of equal parts.
The Japanese Empire Department of Education displayed this rule at the 1876 Centennial Exhibition in Philadelphia. It then was held by the Museum of the U.S. Bureau of Education before transfer to the Smithsonian in 1910. For more information, see MA.261298 and MA.261313.
Currently not on view
date made
before 1876
place made
Physical Description
brass (overall material)
overall: .4 cm x 31 cm x 2.5 cm; 5/32 in x 12 7/32 in x 31/32 in
ID Number
accession number
catalog number
Credit Line
Transfer from Bureau of Education, Department of the Interior
Expositions and Fairs
Rule, Measuring
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Scale Rules
Data Source
National Museum of American History


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