I am please to offer from my private collection this  Important historical and exeptionaly rare museum quality 14k solid gold&enamel full hunter case Pivoted Detent Navvy Chronometer Grand Prix Gold Medals winner"La Maisonnette" oversize pocket watch, specially ordered for the cabinet of the first Chinese President  Dr.Sun Yat-Sen.The watch has been awarded by Sun Yat Sen to the Guomindang party minister and Navy Admiral H.K.Tu in act of honor for the succesfull visit of the Admiral Tu in USA,where he meet the US President Hoover. The watch is really impressive-it wear 132g! (over 60g solid gold contain); 55mm in diameter! On the front case is depiced the enamelled portrait of Sun Yat Sen. On the rear case is depiced the Chinese flags,symbol of the union of the nation. The watch has been tested and approved in the Swiss Obesrvatory.Please note that only 3% of Swiss watch production was officialy certified as chronometers! This masterpiece is the MOST PRECISION timekeeper ever invented(excluding the quartz watches)! The movement is fully jeweled,with the famous MAXIMUM 5 "CHATONS" settings of the rubys(mounted in gold),bymetal compensateing big balance wheel with a gold weights,special helical spring(such spring you can see only in the navy chronometers),detent regulator,precision  regulator,gold train.The movement is protekted with glass under the dust cover.The watch is fully serviced ! Perfect working order! The watch is in perfect working order,keeping exact time. Fine gold guilloche dial ,Breguet blue steel hands. The watch comes with certificate of authenticity and with the original wooden presentation case. Provenance:the watch comes from the most important watch collection of Mr Ferdinandov(the ex Bulgarian ambasador in China circa 1960's) We gives 2 years guarantee free service for the watch!   If you are not satisfied in any way-money back guarantee. Free shipping to worldwide by DHL overnight courier. We guarantee 48h delivery door to door! Pivoted detent escapement history: During the 18th century, great efforts were made to develop a practical marine chronometer. John Arnold and Thomas Earnshaw, working on entirely different lines, developed the detent escapement, commonly called the 'chronometer escapement', Earnshaw's design being adopted by most makers since. In the modern form of spring-detent chronometer escapement the discharge pallet is just beginning to move the detent to the left. The locking stone will release the tooth of the escape wheel, allowing an escape-wheel tooth to fall on impulse pallet. As the balance's clockwise swing continues, the discharge pallet releases the gold spring, allowing the detent to be returned by detent spring in readiness to receive the next escape-wheel tooth on completion of the impulse. On the return swing of the balance, the discharge pallet is allowed past the detent by the gold spring. This is the only escapement action in the anticlockwise half of its cycle. The action is known as 'single-beat'. The chronometer escapement is even more detached than the lever; another great advantage is that the escape-wheel teeth and discharge pallet require no oil. Originally most makers mounted the detent on pivots, with a separate adjustable return spring. This system was used extensively by European makers during the 19th century, but the necessity of oiling the pivot holes was a disadvantage, and the detent and spring formed from one piece of steel is usually found in marine chronometers.