{"product_id":"montre-seiko-vintage-twin-quartz-9721-5050-plaque-or-1980","title":"Seiko Vintage Twin Quartz Watch 9721-5050 — Gold-Plated (1980) ","description":"\u003ch2\u003eTwo quartz oscillators in a 1980 dress watch\u003c\/h2\u003e\n\u003cp\u003eThis Seiko Twin Quartz watch, reference 9721-5050, produced in March 1980, can be worn equally well by a man or a woman, with a 29.5mm gold-plated case whose octagonal shape — a rectangle with its four corners cut off — belongs to the formal vocabulary of the late 1970s. Its 6.5mm thickness places it firmly in the dress watch category. The crown, golden and fluted, is set into a recess in the case band.\u003c\/p\u003e\n\u003cp\u003eThe gold dial features twelve black Roman numerals arranged around the outer edge, with a printed minute track along the perimeter. The center is occupied by a slightly recessed octagonal surface, which echoes the geometry of the case and creates a second frame within the first. The black baton hands stand out sharply against it, accompanied by a very fine golden seconds hand.\u003c\/p\u003e\n\u003cp\u003eWhat this understated dial does not reveal is the technology that drives it. Caliber 9721 is a \u003cstrong\u003eTwin Quartz\u003c\/strong\u003e movement: it contains \u003cstrong\u003etwo quartz oscillators\u003c\/strong\u003e instead of just one, the second serving to continuously correct the thermal drift of the first. Seiko thus addressed the main flaw of battery-powered watches of the period, whose rate varied according to wrist temperature. This family of calibers, produced from 1979 to 1981, equipped the brand’s upper ranges.\u003c\/p\u003e\n\u003cp\u003eThe movement incorporates two functions absent from ordinary quartz watches: a \u003cstrong\u003eend-of-battery indicator\u003c\/strong\u003e, which makes the seconds hand advance in two-second jumps when the power weakens, and \u003cstrong\u003ehacking\u003c\/strong\u003e, which stops the seconds hand when setting the time for exact synchronization. The performance levels highlighted at the time of sale were those originally announced by Seiko; on a forty-five-year-old piece, the observed rate depends on the ageing of the movement and its maintenance.\u003c\/p\u003e\n\u003ch3\u003eThree points to note\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTwin Quartz technology\u003c\/strong\u003e — two oscillators instead of one, the second compensating for the thermal drift of the first, reserved for the upper ranges of Seiko.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEnd-of-battery indicator\u003c\/strong\u003e — the seconds hand advances in two-second jumps when the battery weakens, preventing it from stopping without warning.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCase octagonal gold-plated\u003c\/strong\u003e — a rectangle with its four corners cut off, a characteristic design of the late 1970s, with a thickness of 6.5mm.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhy choose a vintage Seiko watch?\u003c\/h3\u003e\n\u003cp\u003eBuying a \u003cstrong\u003evintage Seiko watch\u003c\/strong\u003e rather than a new model means gaining access to a leading Japanese manufacture at a reasonable budget, with pieces whose construction has proven its durability. \u003cstrong\u003eVintage quartz watches\u003c\/strong\u003e from this period are also the easiest to maintain on the pre-owned market: a battery change is enough to get them running again.\u003c\/p\u003e\n\u003cp\u003eTwin Quartz calibers hold a special place among \u003cstrong\u003evintage men’s and women’s watches\u003c\/strong\u003e: they represent the height of Japanese watchmaking research at the end of the 1970s, at a time when Seiko was shifting its prestige ranges from mechanical to quartz. This 29.5mm \u003cstrong\u003evintage dress watch\u003c\/strong\u003e can be worn equally easily by either, slipping under a cuff without difficulty.\u003c\/p\u003e\n\u003cp\u003eLike all our \u003cstrong\u003epre-owned Seiko watches\u003c\/strong\u003e , it has been opened and checked by our watchmakers: verification of the calibre and its consistency with the reference, verification of the serial number, examination of the dial, hands, and case. Each \u003cstrong\u003evintage Japanese watch\u003c\/strong\u003e we offer comes with an invoice Atelier Victor serving as a certificate, a one-year guarantee, and guaranteed lifetime authenticity.\u003c\/p\u003e\n\u003cp\u003e\u003cem\u003e→ \u003ca href=\"\/en\/collections\/montres-seiko-vintage\"\u003eDiscover our vintage Seiko watches\u003c\/a\u003e\u003cbr\u003e→ \u003ca href=\"\/en\/collections\/montres-vintage-japonaises\"\u003eView our selection of vintage Japanese watches\u003c\/a\u003e\u003c\/em\u003e\u003c\/p\u003e\n\u003chr\u003e\n\u003ch3\u003eTechnical specifications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Seiko\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eModel:\u003c\/strong\u003e Twin Quartz\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReference:\u003c\/strong\u003e 9721-5050\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSerial number:\u003c\/strong\u003e 031872\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eYear:\u003c\/strong\u003e March 1980\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOrigin:\u003c\/strong\u003e Japan\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eGender:\u003c\/strong\u003e Men's and women's watch (Unisex)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMovement:\u003c\/strong\u003e High-precision Japanese quartz, calibre Seiko 9721 Twin Quartz (double oscillator, hacking, end-of-battery indicator)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFunctions:\u003c\/strong\u003e Hours, minutes, seconds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCase:\u003c\/strong\u003e Gold-plated, octagonal shape with cut corners (steel caseback)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDimensions:\u003c\/strong\u003e 29.5mm (30.5mm including the crown)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLug to lug:\u003c\/strong\u003e 36.3mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eThickness:\u003c\/strong\u003e 6.5mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLug width:\u003c\/strong\u003e 19mm\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrown:\u003c\/strong\u003e Gold-plated, fluted, original\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDial:\u003c\/strong\u003e Gold, black Roman numerals, recessed octagonal centre, original\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHands:\u003c\/strong\u003e Black baton-shaped, golden seconds hand, original\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eCrystal:\u003c\/strong\u003e Mineral (condition 9\/10)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eStrap:\u003c\/strong\u003e Black crocodile-style leather, not original\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBuckle:\u003c\/strong\u003e Steel pin buckle, not original\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eCondition and guarantee\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eGeneral condition:\u003c\/strong\u003e Good overall condition. The gold dial is even and perfectly legible, the Roman numerals and hands are intact. The Crystal is in very fine condition (9\/10). The gold plating on the case shows visible wear, notably on the upper left corner and the edges, consistent with the age of the piece.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWater resistance:\u003c\/strong\u003e Not guaranteed (vintage watch)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAuthenticity:\u003c\/strong\u003e Lifetime guarantee\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMechanical:\u003c\/strong\u003e Quartz movement checked, new battery, guaranteed for 1 year\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIncluded:\u003c\/strong\u003e Invoice Atelier Victor\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eNot included:\u003c\/strong\u003e Original box and papers\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr\u003e\n\u003ch3\u003eFrequently asked questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is Twin Quartz technology?\u003c\/strong\u003e\u003cbr\u003eIt consists of incorporating two quartz oscillators into the same movement rather than just one. The second continuously measures temperature variations and corrects the drift of the first, which would otherwise be affected by wrist heat and seasonal changes. Seiko developed this approach in the late 1970s for its upper ranges, in a race for chronometric precision that then pitted Japanese manufactures against one another as much as against the Swiss.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow do you know when the battery is running low?\u003c\/strong\u003e \u003cbr\u003eThe movement features an end-of-battery indicator: when the power declines, the seconds hand stops advancing one second at a time and begins moving in two-second jumps. This behaviour indicates that it is time to have the battery replaced, without the watch stopping abruptly. It is a function that entry-level quartz movements did not offer.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is the hacking function?\u003c\/strong\u003e\u003cbr\u003eIt refers to the stopping of the seconds hand when the crown is pulled out to the time-setting position. This makes it possible to synchronize the watch to the exact second with an external reference, rather than accepting a deviation of a few seconds. This function was not systematic on quartz watches of the period.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs a vintage Seiko watch a safe purchase?\u003c\/strong\u003e\u003cbr\u003eIt is, provided that authenticity has been established and the condition is described without reservation. Our watchmakers systematically open the case to verify the calibre and its consistency with the reference, and inspect the dial, hands, and all components. Every pre-owned Seiko watch sold by Atelier Victor comes with an invoice serving as a certificate of authenticity, a one-year guarantee, and authenticity guaranteed for life.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs this piece suitable for a slim or larger wrist?\u003c\/strong\u003e\u003cbr\u003eWith a width of 29.5mm, a Lug-to-lug of 36.3mm, and a thickness of 6.5mm, it suits wrists measuring approximately 15 to 19cm. Its compact format and slim profile place it firmly in the dress watch category, and it can be worn equally well by a man or a woman. The Lug width measures 19mm, making it easy to change the strap.\u003c\/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c\/p\u003e ","brand":"Seiko","offers":[{"title":"Default Title","offer_id":54562798764369,"sku":"031872 9721-5050","price":367.5,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0703\/8576\/2597\/files\/2VD00870.jpg?v=1786737415","url":"https:\/\/ateliervictor.co\/en\/products\/seiko-vintage-twin-quartz-watch-9721-5050-gold-plated-1980","provider":"Atelier Victor","version":"1.0","type":"link"}