Grand Seiko Spring Drives

To start this deep diver about Spring Drive movements, please forget that quartz is equal to battery. This common misconception often leads to the immediate disregard to many beautiful movements such as the exceptionally innovative Spring Drive movement by Grand Seiko.
Grand Seiko Spring Drive Movement
Because Grand Seiko, is Grand Seiko, meaning a fully vertical watch manufacturer born out of necessity. Seiko was formed in Japan in 1881, exceptionally far away from where the Swiss brands were sharing watch manufacturing information. Which distance and propensity for innovation has allowed Grand Seiko to master both electronic and mechanical watchmaking. This movement takes the best of both worlds, with a movement that is largely 85% like your traditional high-end automatic mechanical movement. Like a traditional mechanical movement, a mainspring (here is the “spring” in spring drive), is wound up either by a balance wheel or manual wind to give the watch its energy. Traditionally most mechanical watches rely on the “Swiss lever escapement” to regulate the release of the mainspring’s energy.

This traditional escapement simply cannot compete with the accuracy of a quartz movement which typically uses a battery as its power source to send electricity to a quartz oscillator which vibrate at 32,768 Hz or a frequency of 2^15 cycles per second, much higher than your mechanical watch (which vibrates at 28,800 vph or 4Hz). This exceptionally high Hz rate allows the watch to be accurate within 10 seconds per year versus +8/-1 per day (for Grand Seiko models but also typical of most watch models not COSC certified).

The genius of Grand Seiko’s Spring Drive movement is the combination of the mechanical watch components and the quartz components. The Spring Drive utilizes the mainspring of a traditional watch as its power source that gives the watch the advantage of having a high level of torque. This high-level torque allows the watch to move its long, wide hands in the iconic Spring Drive glide. This is opposed to a quartz-based movement with smaller hands and the “tic” movement of the hands. 

On the other hand, the Spring Drive uses a proprietary speed control mechanism, an electronic brake, a lab grown quartz crystal and an IC. Furthermore, the Spring Drive harmoniously uses three energy sources simultaneously to regulate these moving parts.

integrate circuit of spring drive
  1. Mechanical power from the mainspring
  2. Electrical power which creates a reference signal via an IC (integrated circuit)/quartz oscillator
  3. Electromagnetic power, to apply a brake via a rotor/stator
Mechanical Power- This idea is similar to riding a bike who’s energy is then converted to an electrical power source to power the lights. On the end of the gear train (after the mainspring) a rotor (glide wheel) is connected which makes eight revolutions per second. These revolutions generate an electric current.

Electrical Power- This electrical power is used to activate a quartz oscillator which vibrates exactly at 32,768 Hz to send a precise reference to the IC.

Electromagnetic Power- The integrated circuit compares the signal from the quartz oscillator within the revolution speed of the glide wheel and intermittently applies magnetic brakes which the wheel is operating too quickly. Furthermore, the IC developed by Grand Seiko consumes 1/300,000,000th power of an LED light.

The combination of the tri-synchro regulator gives this movement an accuracy of +/-1 second per day, +/- 15 seconds per month along with a 72-hour power reserve! Additionally, by removing the traditional Swiss lever escapement, there is far less stress applied to the movement. This project was 30 years in the making (started in 1977) after over 600 prototypes and was launched to market in 2007.

Stop by Schwanke-Kasten Jewelers in Whitefish Bay, WI (just north of Milwaukee) to see our beautiful collection of Grand Seiko watches. Many of the Grand Seiko watches at Schwanke-Kasten Jewelers are made with the genius Spring Drive Movement.