{"product_id":"vintage-1978-japan-seiko-ground-twin-quartz-9943-800a-5jewels-quartz","title":"Vintage 1978 JAPAN SEIKO GROUND TWIN-QUARTZ 9943-800A 5Jewels Quartz.","description":"\u003cbr\u003e\u003ch3 style=\"font-size: 32px; color : #2B0000; margin-bottom: 36px;\"\u003eVintage 1978 JAPAN SEIKO GROUND TWIN-QUARTZ 9943-800A 5Jewels Quartz.\u003c\/h3\u003e\u003cp\u003eWelcome to my auction!\u003cbr\u003eI am Japanese who live in Tokyo.\u003c\/p\u003e\n\u003ch4 style=\"font-size: 24px; color : #2B0000; margin-bottom: 18px;\"\u003eItem description\u003c\/h4\u003e\u003cdiv style=\"font-size: 24px; color:red; margin: 0 50px 18px 35px;\"\u003e\nIt's a SEIKO Quartz Watch, \u003cb\u003eGROUND TWIN-QUARTZ 9943-800A 5Jewels \u003c\/b\u003e.\u003cbr\u003e\n\u003cb\u003eIt's in good used condition.\u003c\/b\u003e\u003cbr\u003e\nIt's difficult to find this valuable watch in such a good condition.\nHighly recommended for SEIKO collectors!\n\u003c\/div\u003e\n\u003cdl style=\"margin:0 0 34px 90px\"\u003e\n\u003cdt\u003e\u003cfont color=\"#970000\"\u003e\u003cb\u003eMovement : \u003c\/b\u003e\u003c\/font\u003e\u003c\/dt\u003e\n\u003cdd\u003e\u003cul\u003e\n\u003cli\u003ePet name : 99GQW GROUND QUARTZ.\u003c\/li\u003e\n\u003cli\u003eCaliber number : 9943.\u003c\/li\u003e\n\u003cli\u003eMovement : Quartz.\u003c\/li\u003e\n\u003cli\u003eYear of manufacture start : 1978's.\u003c\/li\u003e\n\u003cli\u003eFactory : Suwa.\u003c\/li\u003e\n\u003c\/ul\u003e\u003c\/dd\u003e\n\u003cdt\u003e\u003cfont color=\"#970000\"\u003e\u003cb\u003eExternals : \u003c\/b\u003e\u003c\/font\u003e\u003c\/dt\u003e\n\u003cdd\u003e\u003cul\u003e\n\u003cli\u003eSerial number : 830451.\u003c\/li\u003e\n\u003cli\u003eDial number : JAPAN 9943-8000 T.\u003c\/li\u003e\n\u003cli\u003eGlass : Crystal.\u003c\/li\u003e\n\u003cli\u003eCase size : About 35.5mm.\u003c\/li\u003e\n\u003cli\u003eLug width : 19mm.\u003c\/li\u003e\n\u003cli\u003eBand : New Leather Strap of SEIKO original.\u003c\/li\u003e\n\u003c\/ul\u003e\u003c\/dd\u003e\n\u003cdt\u003e\u003cfont color=\"#970000\"\u003e\u003cb\u003eCondition : \u003c\/b\u003e\u003c\/font\u003e\u003c\/dt\u003e\n\u003cdd\u003e\u003cul\u003e\n\u003cli\u003eUsed, it runs well.\u003cb\u003e Battery replaced\u003c\/b\u003e\n\u003c\/li\u003e\n\u003cli\u003eQuick set(Day\/Date) : Okay. \u003cbr\u003eSet the day of the week can be in English or Kanji. \u003cbr\u003eSet of the date : The set at one stage pulling the crown.\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eApproximate watch rate at Japan : Quartz.\u003c\/li\u003e\n\u003cli\u003eFor practical, everyday use, it would be advisable to have the movement cleaned and oiled.\u003c\/li\u003e\n\u003c\/ul\u003e\u003c\/dd\u003e\n\u003cdt\u003e\u003cfont color=\"#970000\"\u003e\u003cb\u003eKey Features\u003c\/b\u003e\u003c\/font\u003e\u003c\/dt\u003e\n\u003cdd\u003e\n\u003cli\u003e\n\u003cb\u003eThe Sovereign Apex of 1978 High-Precision Luxury (1978):\u003c\/b\u003e Manufactured in **1978**—a historic milestone year representing the ultimate pinnacle of Japan's electronic horological revolution—the **Seiko Grand Twin-Quartz** stood at the absolute top tier of Suwa Seikosha's executive collection. Sourced under reference **9943-800A**, this flagship timepiece inherited the supreme prestige of the Grand Seiko line, offering unmatched ultra-high precision wrapped in sharp, forward-looking late-1970s Showa-era styling.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eThe Revolutionary 5-Jewel Caliber 9943 Twin-Quartz Engine:\u003c\/b\u003e Powering this historic watch is the legendary **5-jewel Caliber 9943**, an in-house electronic masterpiece utilizing dual paired quartz crystal oscillators. One crystal provided standard timekeeping frequency, while the second detected ambient temperature fluctuations to continuously self-adjust and offset thermometric drift. Built with a robust **5-jewel specification** to control gear-train pivot wear, it achieved an astonishing accuracy standard of within **±10 seconds per year**, featuring **hacking seconds** and quick-set dual calendar functionality.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eArchitectural \"\"8000\"\" Angular Case and Integrated Geometry:\u003c\/b\u003e The reference **9943-800A** is globally distinguished among vintage collectors for its distinct, sharp-edged integrated case architecture. Executed in solid stainless steel, the case features flat, razor-sharp facets and sweeping, angular lug contours finished with zero-distortion mirror polishing inspired by Taro Tanaka's **\"\"Grammar of Design\"\"** principles, allowing the watch to sit remarkably flat and balanced on the wrist.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eMasterful Textured Dial and Applied Twin-Quartz Emblem:\u003c\/b\u003e The dial of the **9943-800A** showcases remarkable depth, featuring a fine textured canvas paired with **hand-applied, multifaceted rectangular hour indices** and razor-sharp hands. Symmetrically framed at 3 o'clock, the dual-calendar window houses a **bilingual (English\/Kanji) day disk** alongside the date wheel, proudly bearing the applied **\"\"GRAND QUARTZ\"\"** typography and the iconic double-comb **Twin-Quartz logo** above 6 o'clock.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAn Investment-Grade Masterpiece of Suwa's Electronic Heritage:\u003c\/b\u003e Manufactured in the milestone year of **1978**, the 9943-800A Grand Twin-Quartz remains one of the most historically significant, highly sought-after cornerstone references for serious vintage Seiko collectors worldwide. It captures the exact historical moment where Japanese electronic engineering achieved supreme luxury status alongside mechanical horology. Built to an uncompromising heirloom standard, it stands as an eternal testament to late-1970s Japanese watchmaking innovation.\u003c\/li\u003e\n\u003c\/dd\u003e\n\u003c\/dl\u003e\n\u003cdl style=\"margin:0 0 34px 40px\"\u003e\n\u003cdt style=\"font-size: 24px;font-weight: bolder;\"\u003eFor more information, please look at the pictures.\u003c\/dt\u003e\n\u003cdd\u003e\u003cdiv style=\"margin: 14px 0 40px 0;\"\u003e\u003cimg src=\"https:\/\/nonkun.boy.jp\/img_ebay\/v1236941643.jpg\"\u003e\u003c\/div\u003e\u003c\/dd\u003e\n\u003cdt style=\"font-size: 24px;font-weight: bolder;\"\u003eNotes\u003c\/dt\u003e\n\u003cdd\u003e\n\u003cul style=\"margin-bottom: 18px;\"\u003e\n\u003cli\u003e\n\u003cb\u003eBefore buying.\u003c\/b\u003e\u003cdiv style=\"padding-left : 30px;\"\u003eThe vintage watches we sell are inspected and adjusted so they work fine. However, since it is an vintage watch, Please purchase on the assumption that it will be repaired.\u003c\/div\u003e\n\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eTo prevent shipping accidents.\u003c\/b\u003e\u003cdiv style=\"padding-left : 30px;\"\u003ePlease monitor the tracking number until the item arrives and if it stagnates, please investigate at your country post office. Also, please confirm the item when you receive the item.\u003c\/div\u003e\n\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAbout import taxes.\u003c\/b\u003e\u003cdiv style=\"padding-left : 30px;\"\u003eTaxes such as import duties and VAT are not included in the item price or shipping charges, except for items shipped to the US. When you purchase, you will likely be required to pay these fees in your country.\u003c\/div\u003e\n\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eAbout Payment, Shipping, Return.\u003c\/b\u003e\u003cdiv style=\"padding-left : 30px;\"\u003ePayment, Shipping, Return are in accordance with eBay's business policies.\u003c\/div\u003e\n\u003cbr\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/dd\u003e\n\u003c\/dl\u003e\u003cbr\u003e","brand":"Seiko","offers":[{"title":"Default Title","offer_id":52078112538945,"sku":"v1236941643","price":89900.0,"currency_code":"JPY","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0995\/8205\/0625\/files\/57_af795bcf-539b-4c24-b15e-bf1af9afe9b6.jpg?v=1786515374","url":"https:\/\/nonkun.com\/products\/vintage-1978-japan-seiko-ground-twin-quartz-9943-800a-5jewels-quartz","provider":"NONKUN Japan","version":"1.0","type":"link"}