{"product_id":"vintage-1971-japan-grand-seiko-weekdater-5646-8000-25jewels-automatic","title":"Vintage 1971 JAPAN GRAND SEIKO WEEKDATER 5646-8000 25Jewels Automatic.","description":"\u003cbr\u003e\u003ch3 style=\"font-size: 32px; color : #2B0000; margin-bottom: 36px;\"\u003eVintage 1971 JAPAN GRAND SEIKO WEEKDATER 5646-8000 25Jewels Automatic.\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 Automatic Watch, \u003cb\u003eGRAND SEIKO WEEKDATER 5646-8000 25Jewels \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 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 : 56 GRAND SEIKO WEEKDATER .\u003c\/li\u003e\n\u003cli\u003eCaliber number : 5646A.\u003c\/li\u003e\n\u003cli\u003eMovement : Automatic.\u003c\/li\u003e\n\u003cli\u003eBeat rate : 28800bph.\u003c\/li\u003e\n\u003cli\u003eYear of manufacture start : 1970'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 : 1N0767.\u003c\/li\u003e\n\u003cli\u003eDial number : JAPAN 5645-8000T.\u003c\/li\u003e\n\u003cli\u003eGlass : Crystal.\u003c\/li\u003e\n\u003cli\u003eCase size : About 35.7mm.\u003c\/li\u003e\n\u003cli\u003eLug width : 18mm.\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.\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.\u003c\/li\u003e\n\u003cli\u003eThe day difference time of an used watch is about +-1 minute \/ day.\u003c\/li\u003e\n\u003cli\u003eFor practical, everyday use, it would be advisable to have the movement cleaned and oiled.\u003c\/li\u003e\n\u003cli\u003e\u003cfont color=\"#9b2166\" size=\"5\"\u003e\u003cb\u003eA small chip is visible on the edge of the glass.\u003c\/b\u003e\u003c\/font\u003e\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 Pinnacle of Suwa Mechanical Mastery (1971):\u003c\/b\u003e In **1971**, the **56 Grand (56GS)** represented the absolute peak of automatic precision before the industry shifted toward quartz. The reference **5646-8000** was produced by the **Suwa Seikosha** factory during a landmark era of horological achievement. It arrived as a high-frequency instrument of clinical accuracy, intended to provide the global elite with a \"\"Grand\"\" standard of timekeeping that surpassed the finest Swiss chronometers.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eThe High-Beat Caliber 5646 Heart:\u003c\/b\u003e This watch is powered by the **25-jewel Caliber 5646A**, a sophisticated automatic movement operating at **28,800 vibrations per hour (8 beats per second)**. In **1971**, this \"\"Hi-Beat\"\" frequency was engineered to provide superior stability against external shocks. The 56-series was a breakthrough in slim-profile design, featuring **hacking seconds**, manual winding capability, and an instantaneous day-date change, all housed within a remarkably thin architecture.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003ePurest Execution of the \"\"Grammar of Design\"\":\u003c\/b\u003e The reference **5646-8000** is a definitive example of the **Style**. The case features flat, mirror-polished surfaces and razor-sharp, multifaceted lugs designed to catch and reflect light with surgical precision. In **1971**, this architectural rigor followed the principles of Taro Tanaka, ensuring the watch would \"\"sparkle\"\" on the wrist and visually communicate the high status and professional discipline of its owner.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eMasterful \"\"Weekdater\"\" Dial Symmetry:\u003c\/b\u003e The dial of the **5646-8000** is a study in functional luxury, featuring a radiant sunburst silver finish and **hand-applied, multi-faceted baton indices**. The dual-calendar window at 3 o'clock houses a **bilingual (English\/Kanji) day disk**, providing an organized, professional aesthetic. The applied **\"\"GS\"\" logo** and the Suwa factory symbol at 6 o'clock remain iconic hallmarks of this era’s uncompromising quality and prestige.\u003c\/li\u003e\n\u003cli\u003e\n\u003cb\u003eA Landmark of Showa-Era Horological Art:\u003c\/b\u003e Produced in **1971**, the Grand 5646-8000 remains one of the most coveted \"\"Grail\"\" watches for vintage collectors worldwide. It represents the final, glorious peak of the mechanical era, combining **heavy-duty engineering with a timeless, minimalist aesthetic**. It stands as a testament to the era when Suwa Seikosha perfected the high-end automatic, creating a mechanical masterpiece that remains as accurate and visually stunning today as it was half a century ago.\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\/g1223053146.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":52078111654209,"sku":"g1223053146","price":234500.0,"currency_code":"JPY","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0995\/8205\/0625\/files\/57_1a379ec6-cccf-49bd-93f2-ee2a9d4f1364.jpg?v=1786515353","url":"https:\/\/nonkun.com\/products\/vintage-1971-japan-grand-seiko-weekdater-5646-8000-25jewels-automatic","provider":"NONKUN Japan","version":"1.0","type":"link"}