Unique Swiss silver lever chronometer navigation watch Circa 1943

Silver deck watch with a wooden deck box
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An exceptionally fine and unique, large Swiss silver keyless pocket watch, circa 1943.
An extra adjusted lever chronometer navigation watch with Guillaume balance, power reserve indication at nine o’clock and seconds at three o’clock. Accompanied by the Extract from the Archives and wooden deck box. The movement was made in 1920 and encased in 1943, sold on December 30th, 1953. A polished case and a hinged silver cuvette. Brushed silvered dial with radial champlevé Roman numerals, outer minute track, subsidiary seconds at three o’clock, 36 hour power reserve indication at nine o’clock and blued steel spade hands.
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A rhodium plated movement, Geneva striping decoration, pillar plate under the dial with oeil de perdrix finishing, 23 jewels, adjusted Extra, very high quality straight line calibrated equidistant lever escapement, Anibal brass Guillaume compensation balance with poising wings on the balance arm, gold and platinum temperature and meantime adjustment screws, blued steel Breguet balance spring with inner and outer terminal curves, ruby banking pins in the shape of small plates inserted into the bridge, punched twice with Seal of Geneva Quality marks, swan neck micrometric regulator, wolf’s tooth winding, special mainspring ratchet wheel clicks preventing over winding and Maltese Cross stop work.
Dial, case and movement signed, case punched with Swiss and German silver marks.
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Diameter: 60 mm
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Signed: Patek, Philippe & Cie.  Genève
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The present watch is a very fine example of a Patek Philippe navigation watch from a very small series, all destined for Observatory trials. This particular watch would appear to be unique in this series. To date, it is the only known example with the power reserve indication at 9 o’clock and the subsidiary seconds at 3 o’clock instead of the usual 12 o’clock and 6 o’clock positions. To facilitate this dial configuration, the wheel train of the movement itself has had to be re positioned and therefore specially made so that the fourth wheel pinion is in the 3 o’clock position to carry the second hand. The going barrel is in the 9 o’clock position for the power reserve indication.
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The movement has the unusual winding click and Maltese cross stop work to prevent overwinding found on very few Patek Philippe watches. When destined for Observatory Timing Contests, the movements of Patek Philippe watches, like those of other makers, were double engraved with the movement serial numbers. Interestingly, the present watch does not bear the usual inscription “Extra” on the bridge of the movement referring to the high finishing of all the parts of the movement, however, the Extract from the Archives confirms that movement No. 191833 is indeed Extra quality. The case also bears a German import mark for silver indicating that it was intended for use by the German Navy. Very few navigation watches of this series were supplied by Patek Philippe, perhaps due to their high prices.