Antiquorum Auctioneers since 1974

Geneva, May 09, 2026

LOT 252

ECOLE D'HORLOGERIE GENEVOISE, SWITZERLAND, “PIÈCE ÉCOLE”, MADE BY JACQUES BERTHET, PATEK PHILIPPE CALIBER, STAINLESS STEEL

CHF 6,000 - 10,000

HKD 60,000 - 100,000 / USD 7,600 - 12,700 / EUR 6,500 - 10,900 / JPY 1,210,000 - 2,020,000

Sold: CHF 11,875

A very fine and rare, stainless steel open-face chronometer pocket watch from the Geneva watchmaking school, made by Jacques Berthet, polished case with geometrical bow. Glazed snap-on case back revealing the movement. Silver brushed dial with applied faceted steel indexes, outer minute track, subsidiary seconds at six o’clock. Steel Dauphine hands. Movement by Patek Philippe, stamped twice with the Geneva Seal, fitted with a swan-neck micrometric regulator.


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Grading System
Grade: AAA

Excellent
Case: 3

Good
Movement: 3*

Good

Overhaul recommended, at buyer's expense
Dial: 3-01

Good

HANDS Original

Brand Ecole d'Horlogerie Genevoise, Switzerland

Model “pièce école”

Year Circa 1940-1950

Movement No. 340

Caliber 19’’’, 42 mm., 19 jewels, rhodium-plated movement with fausses côtes decoration, going barrel, straight-line lever escapement, cut bimetallic compensated balance with gold poising screws and blued steel hairspring with terminal curve, polished steel index regulator with swan-neck spring and micrometric screw. “Poinçon de Genève” (Geneva Seal) stamped twice on the main plate and bridge.

Diameter 50 mm.

Signature Dial and movement

Notes

School watches produced at the École d’Horlogerie de Genève formed an essential part of the training of advanced watchmaking students. These pieces were generally executed as examination watches and were largely made, finished and adjusted by the student under the supervision of the school’s master instructors, demonstrating mastery of precision chronometry and traditional finishing techniques.

In a number of cases, the movements used for these watches were supplied by prestigious Geneva manufactures such as Patek Philippe, Vacheron Constantin.... The ébauche or partially finished movement would then be completed, adjusted, decorated and regulated by the student, often to a very high standard comparable to that of professional chronometers.

Some examples also bear the prestigious Poinçon de Genève, one of the most demanding quality hallmarks in watchmaking. This certification guarantees that the movement was assembled and adjusted in the Canton of Geneva and that it meets strict criteria regarding construction, finishing and reliability. The presence of this hallmark on a school watch highlights the exceptional level of craftsmanship achieved by the student and the close relationship between Geneva’s watchmaking industry and its educational institutions.