{"product_id":"rolex-perpetual-bulging-back-18k-pose-gold-1950s","title":"ROLEX  PERPETUAL BULGING BACK 18k Rose Gold 1950s","description":"\u003cp\u003e\u003cspan\u003ePatent No. 144350.\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eFiled in 1929 by Rolex, \u003c\/span\u003e\u003cspan\u003ethis marked the company’s first application for a self-winding mechanism—\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003ea development that would fundamentally reshape the watch industry.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis evolution led to the perpetual system that would later define the brand.\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eThe first patent concerning the automatic rotor—Patent No. 160492—\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eis widely attributed to Emil Borer of Aegler.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eFurther advancement came with Patent No. 170803, filed in 1933, \u003c\/span\u003e\u003cspan\u003ewhich established the foundation of the rotor system later associated with the “Bubbleback.”\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis mechanism enabled bidirectional winding through two reversing wheels, \u003c\/span\u003e\u003cspan\u003eeach fitted to prevent counter-rotation, ensuring efficient transmission of energy regardless of direction.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003ePower from the rotor was transferred to the mainspring via ratchet-equipped gears, \u003c\/span\u003e\u003cspan\u003eminimizing backlash, while additional components—\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eincluding a three-armed, curved disc—\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eallowed the automatic module to be mounted above the movement’s primary gear train.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis vertical layering required additional height, \u003c\/span\u003e\u003cspan\u003emaking it necessary to expand the caseback.\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eThis structural necessity is the origin of the Bubbleback form.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe first Bubbleback models appeared in 1933.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eEarly examples featured engraved instructions inside the caseback, \u003c\/span\u003e\u003cspan\u003eguiding watchmakers during disassembly from the rotor side—\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003ea practical solution for what was, at the time, an unfamiliar construction.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThese markings disappeared in the second generation,\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eand by the third, the movement had evolved into Caliber 620, \u003c\/span\u003e\u003cspan\u003eintroducing the NA size for the first time.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eAs other manufacturers began downsizing their calibers\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eto enable broader model variations, \u003c\/span\u003e\u003cspan\u003eRolex followed with similar developments.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIn 1936, the reduced-size AR movement—Caliber 520—was introduced.\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eThat same year also saw the debut of the 530AR, \u003c\/span\u003e\u003cspan\u003ea center-seconds movement for ladies’ models.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe present model emerges from this lineage.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eRef. 4643\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eProduced for only six years, from 1946 to 1952, \u003c\/span\u003e\u003cspan\u003eit stands as a rare example of a rectangular Rolex.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eCrafted in solid 18k rose gold, \u003c\/span\u003e\u003cspan\u003eits case exhibits a rich, deep-toned luster with strong visual presence.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eDespite its 28mm dimensions, \u003c\/span\u003e\u003cspan\u003eits proportions give the impression of a 34mm round watch.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eWhile it features a perpetual mechanism, \u003c\/span\u003e\u003cspan\u003eit does not conform to the Bubbleback structure.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eInstead, it employs a square case with a subtle curvature—\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eoften mistaken for a Bubbleback, but fundamentally different.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThe essence of the Bubbleback lies in three defining elements: \u003c\/span\u003e\u003cspan\u003ea domed caseback, water resistance, and a perpetual (self-winding) system.\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eThese characteristics were clearly communicated by Rolex in period advertising.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis reference, therefore, must be understood on its own terms.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eAt its core lies the significance of Caliber 520AR.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eFrom its early years, Rolex implemented a system\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003ein which discrepancies between movement production and case availability \u003c\/span\u003e\u003cspan\u003ewere managed by fitting older movements into newer cases.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis was not incidental, but a deliberate and efficient operational strategy.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eIn this piece, a movement produced in 1936 \u003c\/span\u003e\u003cspan\u003ewas installed into a watch assembled in 1946.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003eThis detail reflects more than specification—\u003c\/span\u003e\u003cspan\u003e\u003cbr\u003e \u003c\/span\u003e\u003cspan\u003eit reveals the essence of Rolex as a company: \u003c\/span\u003e\u003cspan\u003ea family-run enterprise built on precision, discipline, \u003c\/span\u003e\u003cspan\u003eand a long-term vision for sustainable success.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp data-start=\"641\" data-end=\"733\" data-is-last-node=\"\" data-is-only-node=\"\"\u003e\u003cstrong\u003e- wrist size in our picture is 17cm circumference -\u003c\/strong\u003e\u003c\/p\u003e","brand":"Vintage Rolex Watches","offers":[{"title":"Default Title","offer_id":53283540107571,"sku":null,"price":1920000.0,"currency_code":"JPY","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0976\/1076\/0499\/files\/75562689-E4B6-4A81-84B4-0950CDF9A518.jpg?v=1777006655","url":"https:\/\/principe-prive-epocadoro.com\/products\/rolex-perpetual-bulging-back-18k-pose-gold-1950s","provider":"PRINCIPE PRIVE - Epoca d'Oro","version":"1.0","type":"link"}