Japanese Folding Scale Rule

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This metal rule unfolds to a length of 14-7/8" (38 cm). One side is divided into ten units of 1-1/2" (3.7 cm). The units are subdivided into 20 parts. The hinge is shaped like a protractor. It is divided unevenly into five units marked with Japanese characters that have not been translated. From the right, the divisions are at approximately 10°, 30°, 60°, 90°, and 135°.
The other side has a scale 30.3 cm long that is divided into ten sun, a traditional Japanese unit of length that is 1/10 of a shaku, a "foot" measure. Each unit is 1-3/16" and is subdivided into 20 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
steel (overall material)
overall: .2 cm x 19.8 cm x 1.8 cm; 3/32 in x 7 25/32 in x 23/32 in
ID Number
catalog number
accession 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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