French gold enamel open faced keywind pearl set pocket watch Circa 1790

Gold and enamel pocket watch by Hefsen
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A French gold and enamel pearl set open faced keywind pocket watch, circa 1790. Gilded full plate movement featuring a verge escapement, a centrally mounted pierced and engraved balance bridge, a fusee and chain, and silvered regulation.
The white enamel dial is adorned with black Arabic numerals and includes a winding square at 2 o’clock. The gold case has a blue guilloché enamel reverse, pearl set bezels, and a band decorated with alternating strung seed pearls and a twisted enamel ribbon design.
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Diameter: 42 mm
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Signed: Hefsen à Paris
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The dial is chipped around the winding aperture, and the movement is not functioning. The case band is extensively damaged, with losses to the seed pearls and enamel. The case back appears to have been restored with soft enamel and is loose within the case.