The Seiko Spring Drive: Innovation and Refinement, Part 3

A Visit to the Seiko Epson Factory, in Shiojiri, Nagano prefecture

Upon completion of our meeting with the Seiko Watch Corporation executives, we caught a train at Shinjuku station – destination: the town of Shiojiri in the mountains of Nagano prefecture.  Nagano, of course, was the location of the 1998 Winter Olympic Games, but is also the home of the Seiko Epson division of the Seiko Corporation.

Suwa City, Nagano Prefecture
Sunset in Suwa City, Nagano Prefecture.  Home of the Seiko Epson Corporation.

Seiko Epson is one of the "prime contractors" for Seiko Watch Corporation's model production - the other being its sister company, Seiko Instruments.  While the headquarters for Seiko Epson are found in Suwa City, the factory which makes high-end Spring Drive, Grand Seiko, and Credor watches for the Watch Operations Division, is located in the town of Shiojiri, a short distance away.

Ordinary looking from the outside, Seiko Epson’s watch factories stand tall in horological history – this was the birthplace of the first Japanese automatic watch (1959), the first quartz wristwatch (1969), the winner of the last Swiss Observatory Mechanical Chronometer Competition (1969), the first LCD wristwatch (1973), the first autoquartz (“Kinetic”) watch (1987), and the world’s thinnest quartz movement at 0.85mm (1989).  Currently, this factory serves as the only location where Spring Drive movement and final watch assembly is performed.

Seiko Epson
A Technical Briefing at Seiko Epson - (l to r) - Takeo Murata, Kaoru Iida, Tatsuo Hara, Junya Kamijo

After a welcome by Mr. Kaoru Iida, General Manager of the Watch Brand Department, we are given a technical briefing and demonstration of the Spring Drive mechanism by Mr. Tatsuo Hara, who was one of the developers of the Spring Drive technology working with Yoshikazu Akahane.  Mr. Hara gave us a detailed description of how the Spring Drive movement works, using the Tri-Synchro Regulator in place of the traditional lever escapement.

Tatsuo Hara Demonstration
Tatsuo Hara Demonstrates the braking of the Glide Wheel of the Tri-Synchro Regulator

In addition to the Tri-Synchro Regulator, the innovative Magic Lever winding system originally developed in 1959 is also demonstrated.  This bi-directional dual-pawl winding system is both simple and efficient – and in Spring Drive trim is 30% more efficient than traditional click-wheel based automatic winding systems.  (Ron DeCorte will soon be sharing an in-depth investigation of a pre-production prototype of the movement, including both the Tri-Synchro Regulator and the Magic Lever.  However, allow me to give a small preview - the theory and implementation of the Spring Drive is both elegant and ingenious.

After the briefing, we are led on a tour of the actual workshop facilities.  Seiko Epson has only five watchmakers who they have certified to perform final assembly and checking of the Spring Drive movement – Mr. Junya Kamijo, Ms. Satomi Nakajima, Ms. Toshie Tokunaga, Mr. Hitomi Sakai, and Ms. Kaori Washimi.  All have distinguished themselves in national and international watchmaking skills competitions.

Junya Kamijo
Junya Kamijo, Manager, Watch Technical Engineering Workshop, works on the Spring Drive Automatic

In the Takumi (“Master”) Studio area, we are led by a series of glass windows enclosing the movement assembly and component build-up areas.  The air conditioning and lighting systems are specialized, to ensure a clean environment for the watches and optimum vision for the watchmakers.

Jeweling of a Spring Drive base plate.  The actual setting of parts is performed by hand, not machine

The watchmakers all wear white lab coats, and use finger cots or gloves to ensure that their skin oils do not contaminate movements, cases, or dials.  Much of the small-scale work is performed under binocular microscopes rather than loupes. 


While there are plenty of computerized devices in use (e.g. computer controlled positioning of a base plate that is being jeweled, measurement of jewelling depth, etc.), all of the actual building and assembling is done by hand.  Each of the five Spring Drive watchmakers is responsible for the complete assembly of the movement from start to finish, in order to ensure high quality.

Credor Skeleton
A Credor Skeleton Manual Wind Masterpiece
(Click here for a larger photo)

Downstairs from the Takumi Studio is the machining area where dials and hands are manufactured.  Again, the machines are operated by hand and parts are inspected by eye via microscope, instead of relying on automation.

Making Indicies
This craftwoman makes applied markers for dials, driving the machinery by hand

Indicies made from gold wire
Gold Wire attached to a spinning drum is machined down to form indicies

Making Hands
The Making of Hands

Next to the dial and hands manufacturing area is the Micro Design Studio, where gold and platinum jewelry watch cases are shaped and inlaid with stones, again all by hand.

Gem Setting 2
Setting of a Gem in a Jewelry Watch Case

Gem Setting 2
Careful With that Diamond!

Gem Setting 3
Cutting and Setting Another Diamond Case

We were unable to tour the actual case making facility (which is part of this factory), but were shown life size photos of the machinery used to make the case blanks from raw materials.

Case Making Press
A Case Making Press

Our tour wrapped up with an opportunity for your reporter to get a feel for working with the Seiko movements.  We were each given an actual Spring Drive Automatic movement, a few basic watchmaking tools, and a binocular microscope, and were instructed on the disassembly and reassembly of the winding rotor and automatic winding bridge.

Ed Hahn  Joe Thompson
Ed Hahn (left) and Joe Thompson (right) try to become Spring Drive watchmakers.  They do not succeed.

Suffice to say, Seiko Epson did not certify a sixth watchmaker for the Spring Drive assembly line.  Indeed, one hopes that the planned 1,000 watch sales target does not have to be reduced to 996.  However, I am proud to say that I was at least able to successfully complete all steps of the process.

Group Dinner
(top row l to r) - Kenkichi Shibata, Tatsuo Hara, Junya Kamijo, Hiroshi Kamijo, and Bill Shuster (JCK).
(bottom row l to r) - Kaoru Iida, Jordan Rothacker (IWW), Ed Hahn (TZ), and Joe Thompson (Watchtime).

To top off a very busy day, our hosts at Seiko Epson put us up at a traditional Ryokan hotel in Suwa city, and fed us a wonderful Japanese dinner.  Throughout the trip, our hosts were extremely gracious and truly made us feel very welcome.  Yet, none of this was really surprising, as the same attention to detail given to us as visitors is reflected not only in the construction of the new Spring Drive watches that will be introduced this fall, but is also characteristic of the Japanese people and culture.

Tadaaki Ohira
I would like to especially thank Mr. Tadaaki Ohira, who was our organizer, tour guide, shepherd, and impeccable host during our visit. (He didn't get the watchmaking job, either.)

The official Seiko Spring Drive website is:

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