Extremely rare Swiss platinum complicated watch Circa 1947

Open faced lever perpetual calendar with moon phases by Patek Philippe
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An extremely rare Swiss platinum open faced keyless lever perpetual calendar watch with moon phases, circa 1947. Mechanical movement, 18 jewels, bimetallic compensation balance. Silvered dial with applied Arabic numerals, four subsidiary dials for month and leap year indicator, day, date and moon phases and constant seconds. Plain case, snap on back. Case, dial and movement signed, case and movement numbered.
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Diameter: 46 mm
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Signed: Patek Philippe Genève