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Continuing to be the Standard for Measurements in Japan The Prototype Meter and Prototype Kilogram (1890)

Photo of The Prototype Kilogram

For the units of length and weight that are widely used in daily life, the standards in Japan were the "prototype meter" and the "prototype kilogram" made of alloy (platinum 90%, iridium 10%) distributed by the International Committee of Weights and Measures. The definition of the meter was changed to the one based on the speed of light, but the prototype kilogram remains the standard for weight in Japan, even today. The two prototypes are currently stored at the National Metrology Institute of Japan at AIST.

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