The worlds first 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.
 
This model was one of the first Grand Quartz watches, which debuted in 1975. A group of 8 Grand Quartz models were released to the market. Six of the eight introductory models were presented in solid 18k gold cases, costing between 460,000 to 1,350,000 Yen. 
The Stainless models were 80,000 Yen. The movement was originally quoted as having a +/- 5 seconds per month variation. 
 
This reference is desirable due to the linear grained textured dial, decagonal bezel, textured case finish and integrated bracelet with matching finish. This example dates to September of 1975. 
 
The dial is completely original and has a navy-blue base tone which is rich and elegant. The dial is finished to an exceptionally high standard. It has a linear textured finish, which makes this reference stand out. There is a chapter ring inside of the bezel piece which has a mirrored finish. There are three-dimensional applied baton hour markers, white painted to the top which matches the hands.
 
The dial has applied polished Seiko logo with Twin Quartz symbol, with date window applied polished surround. All signing is clear in a white 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 white painted and are in excellent condition.
 
The case is made of Stainless Steel and is in good-average condition. It is a 3-piece case with bezel, centre body and rear of the monocoque movement housing.
The bezel is a decagon, which earns this reference the nickname ‘Royal Oak’, due to its similarity to the bezel of the Audemars Piguet Royal Oak. The centre piece of the case has a textured finish to the top with polished sides. 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 595300. It is also signed ST. Steel, Japan J. The model reference is 4843-7000.
 
The watch its original XOB-310 bracelet which follows the finish of the top of the case. It has comfortable brick style links.
 
The movement is the Quartz calibre 4843A from Seiko, which is keeping time to +6 seconds a month.
 
Full condition report below. Please see the images as these compliment and aid the description provided below.
 
Dial: 
The dial is completely original and is in good condition with no visible marks or discolouration. The twin quartz logo above 6 O’clock has some corrosion.
 
Hands: 
The hands are original and of Index style. They are white painted and are in good condition. The central second hand is also original and is in good condition. 
 
Glass: 
This is the original Hardlex crystal, which is in good condition.
 
Crown: 
The crown is original and is made of Stainless Steel. It has the Twin Quartz logo.
 
Case:
The case is made of Stainless Steel and is in good-average condition. The bezel has some wear to the plate. The centre piece of the case has a textured finish to the top which is in good condition. The polished sides have scratching and dints, but nothing very deep.
 
Caseback:
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 damage.
 
Strap: 
The bracelet is comfortable, long and is in good condition. It will fit any wrist size with slide adjustment.
 
Movement:
The movement is the Quartz calibre 4843A from Seiko. It is in good condition and is working well. It has not been serviced but has had a new battery fitted. It is keeping time to +6 seconds a month.
 
Case dimensions: 
Case width: 36mm
Case width with crown: 38mm 
Case length: 41mm 
Case length lug to lug: 41mm
Case Depth: 11mm
Lug width: 19mm