Swiss 18k yellow gold open faced minute repeater Circa 1920

Gold lever keyless-wind dress watch 
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A fine and elegant Swiss, thin, minute repeating, 18K yellow gold keyless dress watch, circa 1920. Retailed by Boucheron. A polished case, concealed hinge. Hinged gold cuvette. Matte silver dial with champlevé Breguet numerals, outer minute track, subsidiary seconds, engine-turned centre. Blued steel spade hands. A rhodium-plated movement, Geneva striping decoration, 31 jewels, straight-line lever escapement, cut bimetallic compensation balance, blued steel Breguet balance spring, index regulator, repeating on gongs activated by a slide on the band. Dial signed Boucheron, case signed H.N & Co.
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Diameter: 45 mm
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Signed: Haas Neveux & Co.  Genève
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The case has some dents.