The Seiko Spring Drive Explained

In 1969, Seiko introduced one of the most disruptive technologies in the history of watchmaking: the quartz movement. Quartz movements are more accurate than automatic or mechanical movements, generally less temperamental, and are far cheaper to produce. Since then, the Japanese watchmaker has continued to innovate and help the industry evolve with inventions like the kinetic watch, the kinetic auto relay, and now, the Spring Drive.

To understand the significance of the Spring Drive, it probably helps to have a little background on more conventional watch movements.

Mechanical Watches

Mechanical watches contain a main spring, the tension from which drives the watch. The main spring is wound by hand (usually by twisting the crown), at which point it slowly unwinds at a regular rate over the course of a couple of days. Mechanical watches use devices call escapements which provide the friction necessary to cause the main spring to unwind at a rate consistent with units of time (otherwise the main spring would simply unwind all at once). Escapements are the most intricate, delicate, and expensive components of mechanical and automatic watches.

Automatic Watches

Automatic watches typically operate just like mechanical watches, except they use a small weight or rotor to automatically wind the main spring. The weight winds the main spring by pivoting around shaft as you move your arm during your everyday routine. Most automatic watches can also be wound like mechanical watches, though there is seldom a need to do so. Automatic watches are far more common today than mechanical watches (when was the last time you saw someone wind their watch?).

Quartz Watches

Quartz watches operate entirely differently than automatic and mechanical watches. A quartz watch uses electricity from a battery to osculate a tiny quartz crystal at a very high and very predictable frequency. Those vibrations are counted and add up to seconds, minutes, hours, etc. Quartz watches are almost always more accurate than their automatic and mechanical counterparts, usually gaining or losing no more than 15 seconds per month, and in some cases, as few as 20 seconds per year. (It’s usually acceptable for automatic watches to gain as many as 6 seconds per day, or 3 minutes per month.)

Seiko Kinetic Watches

Kinetic watches are sort of a combination of automatic and quartz watches. They contain a weight like automatic watches which responds to arm movements, but rather than winding a main spring, the weight powers a tiny generator which stores power in a capacitor, or a rechargeable battery. That power is then used to power a standard quartz movement, thus giving you the accuracy of a quartz watch, but without a battery that needs to be replaced. It’s worth noting that kinetic watch capacitors do occasionally need to be replaced, but much less frequently than standard watch batteries. I have a Seiko Kinetic watch that is over 6 years old, and the capacitor still works beautifully.

The Seiko Spring Drive

The Seiko Spring Drive actually contains a main spring like an automatic or mechanic watch, but it is made from a material which provides more elasticity than your typical main spring, providing a power reserve of 72 hours as opposed to the more common 40 hours. What is really unique about the Spring Drive, however, is that it does not use an escapement to regulate the unwinding of the main spring. Rather, it uses a “Tri-synchro regulator” which regulates the energy generated by the main spring, and uses that energy to power a crystal oscillator. In other words, the Spring Drive is an even tighter integration between automatic and quartz movements than even kinetic watches because the crystal is directly powered by the main spring rather than a rechargeable capacitor. The result is accuracy of about one second or less per day, and a completely smooth, sweeping hand movement.

The Seiko Spring Drive should be available all over the world (including the US!) sometime after September of 2005. No information on pricing as of yet, but you can bet I’ll be reviewing one of these as soon as I can get my hands on one.

By Christian Cantrell