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For sale we have an July 1978 Seiko Grand Quartz reference 9943-8020, with silver snow dial, on an XBB-240L Stainless Steel bracelet.


The world’s first mass production quartz watch was released in December 1969. Throughout the 1970s there was a cycle of rapid development to transform this new technology from a science like project, into a high-end, cutting-edge form of haute-horology.


Subsequently, these quartz pieces that gave Seiko so much success, cannibalised not just other brands mechanical pieces, but also Seiko’s. As such these names shifted, with Grand Seiko now being revamped as Grand Quartz, making use of fresh quartz technology.


The first Grand Quartz watches debuted in 1975, with the next generation of movements, the Twin Quartz calibres, introduced in 1978.


The Twin Quartz, temperature compensated movements marked the shift from measuring accuracy in terms of an ANNUAL rate, rather than monthly. It was rated at +/- 10 seconds a year. This really was the peak of accuracy and performance. It is a desirable reference to the beautiful silver snow dial and the integrated tooth link bracelet. Combining accuracy and impeccable design with high quality touches, these vintage Grand Quartz watches represent significant value for money.


The original price of the Grand Quartz 9943-8020 with bracelet, was 100,000 Yen.


The dial is completely original and in excellent condition. It is finished to an exceptionally high standard with the texture and tone of the silver snow finish. There is a chapter ring inside of the bezel piece which has a mirrored finish. There are three-dimensional applied baton hour markers, black painted to the centre which matches the handset. The dial has applied polished Seiko logo with Twin Quartz symbol, with the polished applied date window surround. All signing is clear in a black tone. The date window is a clean white finish with black signing. It has English and Japanese on the day and date.


The hands are original and of Index style with neat silver central second hand. They are mirror polished with black painted centre with a sharp bevelled finish.


The case is made of Stainless Steel and is in good original condition. It is a 3-piece case with bezel, centre body and rear of the monocoque movement housing.

The bezel is circular and polished, framing the dial. The centre piece of the case has a textured finish to the top with polished sides. It has an excellent angular design which is complimented by the mix of finishes. To the right is the original crown which is made of Stainless Steel with the Twin Quartz logo.


The case back is a solid piece with battery hatch. It is signed Seiko, with the serial number 870392. It is also signed Water Resist G HSS Back, ST. Steel, Japan J. The model reference is 9943-8020.


The watch its original XBB-240L bracelet which follows the brushed finish of the top of the case. It has comfortable brick style links.


The movement is the Quartz calibre 9943 from Seiko. It is in good condition, with a new battery fitted. It is keeping time to +/- 3 seconds a month.


Full condition report below. Please see the images as these compliment and aid the description provided below.



The dial is completely original and is in very good condition with no visible marks or discolouration. The applied Seiko and twin quartz logo have no corrosion, whilst the signing is all good and clean.



The hands are original and of Index style. They are silver and appear black in some lights due to the mirror polish finish. They are in good condition with no signs of corrosion.



This crystal is original and is in good condition with no obvious marking.



The crown is original and in good condition. It is made of Stainless Steel. It has the Twin Quartz logo.



The case is made of Stainless Steel and is in decent unpolished condition. There is light surface scratching to the brushed face. The battery hatch is in decent condition.



The case back is in good condition for the age, with light surface scratching.

The main face has a brushed finish, slightly worn, whilst the side is polished. The battery hatch is in good condition with only slight signs of marking. The engraving is clear.



The original bracelet is comfortable, long and is in good condition. The brushed finish is good with light surface scratching. It will fit up to an 7.75” wrist diameter.



The movement is the Quartz calibre 9943 from Seiko. It is in good condition with a new battery fitted. It is keeping time to +/-3 seconds a month.


Case dimensions:

Case width: 35.5mm

Case width with crown: 36.75mm

Case length: 41.5mm

Case Depth: 9mm

Lug width: 20mm


July 1978 Seiko Grand Quartz ref 9943-8020 Steel Bracelet XBB-240L

Out of Stock
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