{"product_id":"blancpain-18k-yg-jumping-hour-big-rectangular","title":"BLANCPAIN 18k YG Jumping Hour Big Rectangular 1925s","description":"\u003cp data-start=\"128\" data-end=\"165\"\u003eA mechanism defined by its structure.\u003c\/p\u003e\n\u003cp data-start=\"167\" data-end=\"429\"\u003eAt its core, an intermediate wheel transmits torque to the mainspring, while a fence—designed to match the dimensions of the case—guides a movable base lever.\u003c\/p\u003e\n\u003cp data-start=\"167\" data-end=\"429\"\u003eAs the watch moves vertically, the internal mechanism slides along this fence, activating the system.\u003c\/p\u003e\n\u003cp data-start=\"431\" data-end=\"667\"\u003eA locking click mounted on the base lever, together with a fixed locking click, winds the intermediate wheel and transfers energy to the mainspring.\u003c\/p\u003e\n\u003cp data-start=\"431\" data-end=\"667\"\u003eThis construction can be described as a “lever up-and-down automatic winding system.”\u003c\/p\u003e\n\u003cp data-start=\"669\" data-end=\"763\"\u003eBy embedding ball elements into the sliding section, the mechanism was given the name “ROLLS.”\u003c\/p\u003e\n\u003cp data-start=\"765\" data-end=\"950\"\u003eThis system was developed by Léon Hart, who, under the concept of a “perpetual dream,” established his own workshop in 1911 at the age of 23 and achieved early success in watchmaking.\u003c\/p\u003e\n\u003cp data-start=\"765\" data-end=\"950\"\u003eAt the same time, John Harwood had already developed the first automatic wristwatch system.\u003c\/p\u003e\n\u003cp data-start=\"765\" data-end=\"950\"\u003eIn collaboration with the ébauche manufacturer A. Schild, the movement was adopted by Fortis and presented at Basel in 1926 as the world’s first automatic wristwatch.\u003c\/p\u003e\n\u003cp data-start=\"1219\" data-end=\"1507\"\u003eHarwood later structured his business around licensing production and sales rights rather than direct manufacturing.\u003c\/p\u003e\n\u003cp data-start=\"1219\" data-end=\"1507\"\u003eIn 1926, Blancpain—then possessing exceptional financial strength—secured exclusive distribution rights across Europe, effectively dominating the automatic watch market.\u003c\/p\u003e\n\u003cp data-start=\"1509\" data-end=\"1622\"\u003eWithin this context, it is natural to consider that Hart’s mechanism became of strategic importance to Blancpain.\u003c\/p\u003e\n\u003cp data-start=\"1624\" data-end=\"1744\"\u003eIn 1929, Hart’s system was formalized as the “Hart Patent,” with its development and deployment overseen by Blancpain.\u003c\/p\u003e\n\u003cp data-start=\"1624\" data-end=\"1744\"\u003e \u003c\/p\u003e\n\u003chr data-start=\"1746\" data-end=\"1749\"\u003e\n\u003cp data-start=\"1751\" data-end=\"1825\"\u003e \u003c\/p\u003e\n\u003cp data-start=\"1751\" data-end=\"1825\"\u003eThe present example is equipped with this Hart Patent automatic mechanism.\u003c\/p\u003e\n\u003cp data-start=\"1827\" data-end=\"2032\"\u003eOriginally developed in a ladies’ size, this system was later adapted into a men’s format through collaboration with Blancpain.\u003c\/p\u003e\n\u003cp data-start=\"1827\" data-end=\"2032\"\u003eToday, no other confirmed examples are known to exist on the global market.\u003c\/p\u003e\n\u003cp data-start=\"1827\" data-end=\"2032\"\u003eA defining feature of this watch is its jumping hour display.\u003c\/p\u003e\n\u003cp data-start=\"2102\" data-end=\"2388\"\u003eThe watch uses rotating discs for both hours and minutes, forming a counter-style display without traditional hands.\u003c\/p\u003e\n\u003cp data-start=\"2102\" data-end=\"2388\"\u003eThe hour indication advances in coordination with the minute disc, typically transitioning after the 40-minute mark— a characteristic behavior unique to this system.\u003c\/p\u003e\n\u003cp data-start=\"2102\" data-end=\"2388\"\u003eThe watch is fully automatic and, like the Harwood system, does not feature a crown.\u003c\/p\u003e\n\u003cp data-start=\"2481\" data-end=\"2793\"\u003eTime-setting is performed by opening the case and turning a serrated internal lever by hand.\u003c\/p\u003e\n\u003cp data-start=\"2481\" data-end=\"2793\"\u003eWhile case opening would normally introduce the risk of dust ingress, the integrated fence structure minimizes external entry points, leaving virtually no pathway for contamination aside from the setting lever itself.\u003c\/p\u003e\n\u003cp data-start=\"2795\" data-end=\"2832\"\u003eA thoroughly considered construction.\u003c\/p\u003e\n\u003cp data-start=\"2795\" data-end=\"2832\"\u003eDespite its technical ingenuity, the Hart system was eventually overshadowed by the Harwood design and disappeared from mainstream horological history.\u003c\/p\u003e\n\u003cp data-start=\"2795\" data-end=\"2832\"\u003e \u003c\/p\u003e\n\u003chr data-start=\"2992\" data-end=\"2995\"\u003e\n\u003cp data-start=\"2997\" data-end=\"3219\"\u003e \u003c\/p\u003e\n\u003cp data-start=\"2997\" data-end=\"3219\"\u003eThis example is housed in a solid 18k yellow gold rectangular case.\u003c\/p\u003e\n\u003cp data-start=\"2997\" data-end=\"3219\"\u003eWith approximate dimensions of 28mm by 45mm, it represents an unusually large format for its time— exceeding even the proportions of the Rolex Prince.\u003c\/p\u003e\n\u003cp data-start=\"3221\" data-end=\"3417\"\u003eThe weight of solid gold, combined with the jumping hour display and the rare Hart automatic system, defines the presence of this piece.\u003c\/p\u003e\n\u003cp data-start=\"3221\" data-end=\"3417\"\u003eThe dial and all components remain in original condition.\u003c\/p\u003e\n\u003cp data-start=\"3221\" data-end=\"3417\"\u003e \u003c\/p\u003e\n\u003chr data-start=\"3419\" data-end=\"3422\"\u003e\n\u003cp data-start=\"3424\" data-end=\"3489\"\u003e \u003c\/p\u003e\n\u003cp\u003eFurthermore, to verify the authenticity of this particular instrument, the previous owner directly visited a factory near Geneva that is not even listed on maps, and conducted an investigation.\u003c\/p\u003e\n\u003cp\u003eLocated approximately two hours by train and then one hour on foot, the factory was directly contacted, and a formal confirmation was later received that the instrument was genuine and capable of being overhauled.\u003c\/p\u003e\n\u003cp\u003eIn addition, no similar instrument has been confirmed at the site, and it was reported to be the first time such an instrument had been seen.\u003c\/p\u003e\n\u003cp\u003eA certificate and archive document issued by Blancpain headquarters are included with the instrument.\u003c\/p\u003e\n\u003cp\u003eThis is an extremely difficult instrument to verify the existence of.\u003c\/p\u003e\n\u003cp\u003eWith its structure, history, and verification process, this instrument possesses a complete story.\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cmeta charset=\"utf-8\"\u003e\u003cstrong\u003e- wrist size in our picture is 17cm circumference -\u003c\/strong\u003e\u003c\/p\u003e","brand":"Vintage BLANCPAIN Watches","offers":[{"title":"Default Title","offer_id":53252621304115,"sku":null,"price":5250000.0,"currency_code":"JPY","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0976\/1076\/0499\/files\/126C3889-D5BF-410D-B828-98574F0B29B9.jpg?v=1776671923","url":"https:\/\/principe-prive-epocadoro.com\/products\/blancpain-18k-yg-jumping-hour-big-rectangular","provider":"PRINCIPE PRIVE - Epoca d'Oro","version":"1.0","type":"link"}