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        SeiyaJapan blog — Grand Seiko

        A way to rebirth of Seiko’s mechanical watches Vol.2/ 4S movement

        A way to rebirth of Seiko’s mechanical watches Vol.2/ 4S movement

        Summarized and translated the article, “A way to rebirth of Seiko’s mechanical watches”
        (p.5-9, GS9 "Grand Seiko Magazine / Grand Seiko Nine" TWO, March 2015) 

        Production of the new 4S caliber

        Seiko formed an in-house mechanical watch project team due to the
        positive response received from the 6810 UTD series.
        But no engineer with experience in mechanical caliber design was
        available in a company.

        So, the new caliber, 4S35 was decided to manufacture based on the old
        52 caliber, which was produced 20 years ago.
        The 52 caliber prided itself on precision of the 1970’s Chronometer standard.

        At last, 200,000 4S calibers were produced. Seiko understood it was
        too many. However, manufacturing new caliber costs a lot. Seiko had to
        make 200, 000 calibers.

        The first watch fitted with the 4S was on sale at the end of 1992.
        It was SCVK001 (4S35-8000) with 4S35 caliber.

        Mechanical watches became the focus of attention in the media.
        This boosted Grand Seiko’s mechanical type revival.

        Tanaka wanted to create new Grand Seiko with new high-end caliber. But
        because there were too many 4S caliber surplus, company didn't want to
        develop new caliber.

        As Seiko had to keep to use 4S calibers, they made mechanical watches
        like "Credor Chronometers GBAY992”,  "KING SEIKO 2000 repro model", Laurel, and SUS with 4S calibers.

        Grand Seiko’s mechanical type revival

        Some years later, Seiko began to produce new Grand Seiko with new
        mechanical caliber. It was 1996.

        A young engineer, Jujo Kouichiro tried to fine-tune 4S calibers for new Grand
        Seiko first. But he soon understood it was impossible. Because Grand
        Seiko needs more precision accuracy.

        Each and every retired technical expert was interviewed in order to
        form the new movement.
        Many test products were developed by utilizing 3D CAD computer
        technology. The precision and structure of the test products were
        redone over and over again by ”Ohira Akira”, allowing the completely new movement to be
        completed in just 2 short years.
        (Please search ”Ohira Akira” by Google) 

        The Grand Seiko SBGR001 mechanical type was revived on November 27, 1998.


        The reason I started exporting Japanese wristwatches 

        The reason I started exporting Japanese wristwatches 

        The average Japanese person started using the internet towards the end of the 1990's. I figured I would use the internet to enjoy talking to people from abroad.
        On the internet, there are places known as "forums", where people from all over the world with the same interests can exchange information in English.
        One of those such forums was a place to talk about Japanese wristwatches, or the "Japanese Watch Forum. (It no longer exists).  
        There were few participants on the "Japanese Watch Forum" at the time, but they were all kind to me even with my limited English. 
        Since I live in Japan and was able to read Japanese information, I had more information on "Japanese wristwatches# than the other participants. 
        When I distributed that information in English, it made the participants from abroad very happy.  
        At that particular time, Japanese wristwatch makers didn't distribute much information in English,  so my information had value. 
         Because of that, I started selling Japanese wristwatches on the American auction site, eBay. 

        The same model as the SEIKO watch that I sold on ebay.com first.

        Not many Japanese people used the American eBay site at the time, and since I was in the minority that did, I made a lot of friends. Those people introduced their friends to me, which expanded my network.
        Since PayPal wasn't around at the time, whenever I sold a wristwatch on the American eBay site, I  took US$ Bank money order as payment. It took more than a month, and cost $50 USD in fees in order to exchange them
        For more than 10 years, I was able to export Japanese watches like that,  but the one that stands out the clearest in my memory is Seiko's 4S15 Military product. 
        They were already out of production when I started handling them, so they were difficult to get a hold of. 
        However, it was an extremely popular wristwatch overseas. 
        I was an engineer in an IT related field, but I went to several private shops and pawnshops all over the city on my way home from work and on Sundays, in order to get my hands on new 4S15 Military watches. It made my overseas contacts really happy when I sold them the watches. 

        Seiko SUS automatic 4S15 Movement (28800)

        One of them asked me, ""Why don't you open an online shop?" So I figured "Why not?", and went for it. 
        This net shop job kept me really busy, so I stopped working in the IT field.  
        And this is where I am at now.
        Seiya Kobayashi

        The SBGR001 evolved into the SBGR051 in 2010.

        The SBGR001 evolved into the SBGR051 in 2010.

        The SBGR001 evolved into the SBGR051 in 2010.

        It changed over to a see-through back. (As you already know) 

        The crown got bigger, making it easier to use.

        The date font was made thicker, making it easier to see.  

        The bottom of dial words (Japan 9Sxx-00X0) were made thicker.


        The decorations on movement were also changed.



        It also was given a 72 hour power reserve.

        1. Switching over to an Automatic Winding System

        The Magic Lever System has few parts, making it exceedingly durable.  Winding up the 55 hour main spring was more than efficient.

        *About magiclever 


        Winding up the 72 hour main spring made me realize that the magic lever system has its limits.

        It switched over to the reversing pawl wheels system (is this name right?), which has an efficient winder. The Reverse wheel was made more compact to increase efficiency, and treating the watch with hard coating increased durability.

        *About Reverser

        The winding gears were rechecked, and were made more efficient by going back to using jewel bearings. That is why the number of jewels increased from 26J to 35J

        2. Rethinking the Main Spring .

        The length of the main spring (Spron510)  was lengthened to 10 cm compared to the 9S55, it was widened by 0.5 mm, and it switched over to the 72 hour power reserve. (The main spring was thinned out by 0.2 mm to make it more compact).

        The  9S55 spring is 40 cm long and 0.12 mm thick.
         The 9S65 spring is 50 cm long and 0.10 mm thick.

        Increasing Durability



        1. Improving the Hairspring

        The "Spron610" was used as materials for the hairspring. This doubled the  shock resistance and tripled the anti-magnetization. 

        2. Improving the balance wheel



        The balance wheel mortice was changed from 0.07 mm to 0.08 mm to increase durability.

        3. Improving the gears

        The gears were given a hard coat finish, and some gears were gold-plated with low abrasion resistance to aim for accuracy, making them more durable.




        My favorites Grand Seiko, SBGW031.

        My favorites Grand Seiko, SBGW031.

        The SBGW031 is a retro style wristwatch with a modern design

        based the 57Grand Seiko(43999GS) made in the 1960s.

        With the SBGW031, it is easy to tell the time. It is simple,
        wears well and has an overwhelming sense of existence.


        The SBGW031 embodies the basic concept of Grand Seiko
        and encompasses today’s high technology.


         The three dimensional aspects used in the case
        make even more beautiful.

        The non-reflective glass is sapphire box crystal
        which makes it easier to tell the time and hard to scratch.

        The movement oscillates from 5 to 8
        and the power reserve is close to double. And that’s not all...


        Doesn’t it remind of the relationship between the old Fiat and the new Fiat?

        Image source: Upper left: 
        http://blogs.yahoo.co.jp/oishi_n/30097107.html "Oishi n dialy blog"
        Image source: Bottom right:
        http://car.watch.impress.co.jp/docs/news/photo/20091019_321677.html "Car watch/ Takuya Shouda"

        A way to rebirth of Seiko’s mechanical watches Vol.1


        I summarized and translated the article, “A way to rebirth of Seiko’s mechanical watches” (p.5-9, GS9, March 2015) into English just for your information.

        Since Seiko developed and started to sell a quarts Astron in 1969, Seiko people were less interested in mechanical watches as they thought quarts watches were getting more popular.

        So, when a young Seiko engineer, Jun Tanaka visited Basel World Fair in 1988, he was shocked to see how many Swiss watch makers kept to make mechanical watches with dignity. Some quartz watches could be obsolescence, but mechanical watches might be came down to next generation, he thought. He understood the value of mechanical watches and its future

        Two years after, Seiko sought something special for company’s 110 years anniversary of 1991. Jun, who had been fighting to realize new Seiko mechanical watches in a company proposed a high spec thin mechanical dress watch. It was fortunately accepted by the company.

        Jun and his staff began to manufacture new mechanical watches after long absence for it with “Caliber 6810”.

        “Caliber 6810” were a kind of dead stock. They were slept in a factory because Seiko stopped to create new mechanical watches for two decades. 110 pieces of them were well appreciated by market and sold well. Then, mechanical watches are survived as a product of Seiko. 
        "110th Aniv. U.T.D. 6810-6000 SCQL002" 

        Above is just the first story which Seiko understands the value and start to make it again for mechanical watches.

        Source: “A way to rebirth of Seiko’s mechanical watches” (p.5-9, GS9, March 2015)