Ecole d'horlogerie de Saint Imier wristwatch, “Pièce École” Triple Calendar Chronograph with Moonphase, circa 1950

Record summary

Catalogued by Antiquorum auction archive, Geneva (lot Lot 390-12), this is a wristwatch by Ecole d'horlogerie de Saint Imier, dated c. 1950. The Atlas places it in the Modern Mechanical Horology period (1945 – 1969) of its Wristwatches collection. Materials and techniques recorded by the source: stainless steel. Recorded dimensions: diameter 34 mm. The record is illustrated with 1 photograph.

Assembled from the source record's structured fields. Dates and attributions are given as the source states them; where a field is missing the Atlas leaves it blank rather than estimating.

Catalogue description

Atlas type guide

Chronographs and split-seconds watches

A chronograph is a watch with an additional seconds hand that can be started, stopped and returned to zero independently of the timekeeping. Louis Moinet built an early example in 1816 and Nicolas Rieussec a recording 'chronographe' in 1821; Adolphe Nicole's heart-shaped reset cam (patented 1862) made the modern return-to-zero possible. Split-seconds (rattrapante) chronographs add a second hand that can be stopped for intermediate times; flyback chronographs restart instantly.

Chronographs were essential tools for doctors (pulsometer scales), artillery (telemeter), engineers and sport. In wristwatches, Valjoux, Venus, Lemania and later the automatic chronographs of 1969 (Zenith El Primero, the Chronomatic Calibre 11 group and Seiko 6139) are milestones.

General guidance written by the Atlas editors about this kind of object. It is not a statement about this particular piece; for that, rely on the source record above and on physical examination.

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