Grand Seiko Spring Drive

Presented in 1998 and introduced on the market in 1999, Spring Drive movements have become over the years one of the highlights of the Grand Seiko brand.

This unique technology, the result of decades of research and development, masterfully combines the art of mechanical watchmaking with the precision of quartz.

History of the Spring Drive

In the late 1970s quartz watches were rapidly replacing mechanical ones. It was around that time that engineer Yoshikazu Akahane, employed at Seiko’s Suwa branch, dreamed of a mechanical watch as precise as a quartz one.

It is said that Akahane had an intuition in 1978, when he observed a bicycle descending a hill road at a constant speed thanks to the use of the brakes.

The concept of braking the watch hands, producing a fluid and precise movement without the use of a balance wheel, is the basis of Spring Drive.

In his spare time and on his own initiative, Akahane began to study and draw sketches, but the technologies to create a working model based on his idea did not yet exist at the time.

After several years, during which Akahane returned from time to time to work on his project, in 1982 a first working prototype was completed, even though it only worked for 4 hours.

The turning point came in 1997, when Akahane was placed in charge of the company’s entire watch development division, and decided to make the development of the Spring Drive a top priority.

After more than two decades of research and development, and a total of hundreds of prototypes, the engineer’s dream finally comes true, with the introduction of the first watches with Spring Drive movement.

How does it work

Just like traditional mechanical watches, Spring Drives are powered by a mainspring, which is wound by turning the crown or by an oscillating weight driven by the movement of the wrist.

The energy stored in the mainspring is then transferred to the gears, which determine the movement of the watch hands. There are no batteries of any kind in the Spring Drive: the spring is the only source of energy used to make the watch work.

The fundamental difference compared to traditional mechanical movements is the absence of the balance wheel, which in the Spring Drive is replaced by a Tri-synchro regulator.

The term “Try-syncro” derives from the fact that three different types of energy come into play:

• mechanical, coming directly from the mainspring
• electrical, converted from mechanical energy to power the quartz oscillator
• electromagnetic, to apply a brake via a permanent magnet, which allows to precisely adjust the speed of the hands

One of the main characteristics of the Spring Drive is the smooth glide motion of the second hand, which perfectly represents the natural flow of time.

The Spring Drive movements found in Grand Seiko watches are assembled by hand, and are generally composed of between 200 and 500 parts, depending on the type and quantity of complications.

Each component of the watch is produced in-house, including the quartz crystals, and all finishes are hand-made by highly experienced watchmakers.

Early Spring Drive watches

After more than two decades of development and dozens of prototypes, in 1998 Seiko presented the first official working Spring Drive prototype in Basel.

The following year, in 1999, the first commercial models were introduced, with three limited editions respectively of 500, 300 and 100 units.

The movement used for these models (7R68 or 7R78) is manually wound with a reserve of approximately 48 hours.

The first of the three models, with reference SBWA001 (7R68-0A10), produced in 500 pieces, features a stainless steel case and a distinctive integrated bracelet.

The second model, with reference SBWA002 (7R68-0A20), comes with a solid gold case and leather strap, in a limited edition of only 300 pieces.

The third model differs from the previous ones to be Credor brand, has a platinum case and leather strap and is produced in only 100 pieces, with reference GBLG999 (7R78-0A10).

The 7R78 movement used on the Credor has all the same technical characteristics of the 7R68 that we find in the other two Seiko-branded models, but there are some differences in the finishes.

Caliber 9R65

After more years of research and development to refine the new technology and bring the power reserve to 72 hours, in 2004 the 9R65 movement made its debut. The reference SBGA001 is the first Spring Drive watch to sport the Grand Seiko brand.

The introduction of this self-winding Spring Drive movement marks a turning point for Grand Seiko.

Type	Spring Drive Automatic
Accuracy	±1 sec/day (±15 sec/month)
Power reserve	72 hours
Jewels	30 jewels
Complications	Date, power reserve indicator
Instructions	Instructions 9R65

All Grand Seiko 9R65 watches

Caliber 9R66

In 2006, the 9R66 was introduced, Grand Seiko’s first Spring Drive movement with a GMT function.

Type	Spring Drive Automatic
Accuracy	±1 sec/day (±15 sec/month)
Power reserve	72 hours
Jewels	30 jewels
Complications	Date, power reserve indicator, GMT Dual Time
Instructions	Instructions 9R66

All Grand Seiko 9R66 watches

Caliber 9R86

Gran Seiko’s first Spring Drive chronograph saw the light of day in 2007, with the 9R86 movement, and immediately ranks as the most accurate spring-powered chronograph in the world.

The 72-hour power reserve is maintained even with the chronograph running.

Type	Spring Drive Automatic
Accuracy	±1 sec/day (±15 sec/month)
Power reserve	72 hours
Jewels	50 jewels
Complications	Date, power reserve indicator, GMT Dual Time, chronograph, quick correction function of time difference adjusting to a calendar
Instructions	Instructions 9R86

All Grand Seiko 9R86 watches

Caliber 9R15

Caliber 9R15 is an even more accurate version of the 9R65. The highest level of precision is achieved by selecting with extreme accuracy the quartz oscillators that offer the best performance ever.

On the oscillator there is an 18-karat gold medallion on which the Grand Seiko lion is depicted, which in addition to embellishing the movement represents its high accuracy.

Type	Spring Drive Automatic
Accuracy	±0.5 sec/day (±10 sec/month)
Power reserve	72 hours
Jewels	30 jewels
Complications	Date, power reserve indicator
Instructions	Instructions 9R15

All Grand Seiko 9R15 watches

Caliber 9R84

Type	Spring Drive Automatic
Accuracy	±1 sec/day (±15 sec/month)
Power reserve	72 hours
Jewels	41 jewels
Complications	Date, power reserve indicator, chronograph
Instructions	Instructions 9R84

All Grand Seiko 9R84 watches

Caliber 9R96

Type	Spring Drive Automatic
Accuracy	±0.5 sec/day (±10 sec/month)
Power reserve	72 hours
Jewels	50 jewels
Complications	Date, power reserve indicator, GMT Dual Time, chronograph
Instructions	Instructions 9R96

All Grand Seiko 9R96 watches

Caliber 9R16

Type	Spring Drive Automatic
Accuracy	±0,5 sec/day (±10 sec/month)
Power reserve	72 hours
Jewels	30 jewels
Complications	Date, power reserve indicator, GMT Dual Time
Instructions	Instructions 9R16

All Grand Seiko 9R16 watches

Caliber 9R01

Type	Spring Drive Manual
Accuracy	±0.5 sec/day (±10 sec/month)
Power reserve	192 hours
Jewels	56 jewels
Complications	Power reserve indicator (back)
Instructions	Instructions 9R01

All Grand Seiko 9R01 watches

Caliber 9R02

Type	Spring Drive Manual
Accuracy	±1 sec/day (±15 sec/month)
Power reserve	84 hours
Jewels	39 jewels
Complications	Power reserve indicator (back)
Instructions	Instructions 9R02

All Grand Seiko 9R02 watches

Caliber 9R31

Type	Spring Drive Manual
Accuracy	±1 sec/day (±15 sec/month)
Power reserve	72 hours
Jewels	30 jewels
Complications	Indicatore riserva di carica (back)
Instructions	Instructions 9R31

All Grand Seiko 9R31 watches

Caliber 9RA5

The new-generation caliber 9RA5, introduced in 2020, is the first Spring Drive movement with a sensor to compensate for temperature-induced variations to the vibrations of the quartz crystal.

To prevent the effects of environmental factors such as humidity, light and static electricity, the oscillator and sensor are isolated inside a vacuum-filled capsule.

Type	Spring Drive Automatic
Accuracy	±0.5 sec/day (±10 sec/month)
Power reserve	120 hours
Jewels	38 jewels
Complications	Date, power reserve indicator

All Grand Seiko 9RA5 watches

Caliber 9RA2

Part of the same family as the 9RA5, the 9RA2 introduced in 2021 differs for the power reserve indicator positioned on the back.

Type	Spring Drive Automatic
Accuracy	±0.5 sec/day (±10 sec/month)
Power reserve	120 hours
Jewels	38 jewels
Complications	Date, power reserve indicator (back)

All Grand Seiko 9RA2 watches