Following World War II, Nippon Slide Rule Company (1948 to 1950), later San-Ai Kekki Ltd. (1950 to 1958), produced Relay slide rules which were exported to the USA as Relay Industries. In 1958 the company became San-Ai Measuring Instruments. In 1963 the San-Ai Group joined Riken Optical Co., which eventually became a part of Ricoh Ltd. Ricoh supplied slide rules to many companies in the USA and Europe, such as Compass, Lafayette, Lutz, Sans & Streiffe, Staedtler Mars, and others.
Total number of Relay/Ricoh slide rules in the collection: 3. \(~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\)
|F-686||1961||J.S-3||L||bb||10||yes||Lafayette F-686, Vector Log rule; nice condition|
|150||1972||US-6L||L||bb||10||yes||Sans & Streiffe model 311; very nice condition|
||1974||L||bb||10||yes||Sans & Streife model 312; no date code|