Impressive Swiss gold modern full glazed dress watch Circa 1979

Gold watch with digital calendar and moon phases 
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An extremely fine Swiss 18 carat yellow gold keyless dress watch, circa 1979. With linear ‘American’ digital perpetual calendar and moon phases. Accompanied by the Extract from the Archives and a Patek Philippe service invoice in the amount of CHF 2,160, sold on October 9th, 1979. A modern case with a concave bezel, polished and brushed, correctors on the flat band, inverted U-shaped bow.
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Brushed silver dial, applied yellow gold faceted baton indexes, outer minute divisions, aperture for the digital display of days of the week, months and date. Aperture at 6 for phases of the moon concentric with subsidiary seconds and yellow gold dauphine hands. Rhodium-plated movement, Geneva striping decoration, 18 jewels, straight-line lever escapement, movement stamped twice with Geneva hallmark, cut bimetallic compensation balance adjusted to heat, cold, isochronism and five positions, self-compensating blued steel Breguet balance spring, swan-neck micrometric regulator. Dial, case and movement signed.
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Diameter: 46 mm
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Signed: Patek Philippe  Geneva
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The nearly identical reference 725/2 was in production from 1940 until around 1964. To date, less than 20 examples of this model are known to have survived. The reference 725 is the scarcer of the two references, the difference is that the calendar aperture on this model has rounded ends instead of square ends. The reference 725/4 was made in very few examples towards the end of the production that seemed to have stopped around 1984. Characterised by a square calendar window as well as longer indexes and Arabic 12.
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This example has never been offered at auction and was just completely overhauled at Patek Geneva in May 2014. The American Perpetual Calendar, The linear digital calendar or so-called American Calendar is a calendar in which the date is displayed in a single linear aperture allowing for a legible dial which could be read at a glance. This type of display was invented in the early Art Deco period and is most often found in watches destined for the Anglo-American market. This kind of calendar became popular once again after the Second World War.