Grand Seiko Spring Drive Review

Could the Grand Seiko Spring Drive be the most precise mechanical watch movement ever produced? Discover the secret that makes a Grand Seiko caliber with Spring Drive such a smooth-running movement.

Grand Seiko Spring Drive Review

Many watch enthusiasts, watchmakers, watch collectors, and the like tend to value and appreciate mechanical calibers. What I keep hearing is that it takes more intelligence to create a mechanical watch movement, and that these are not just dazzling works of fine craftsmanship, but mechanical marvels that astonish even the brightest minds. There is an esoteric mystery behind the way they work and a flash of genius that went into their creation. This naturally makes one ask the following question: “Why would Grand Seiko use a quartz crystal in the Spring Drive system of a mechanical movement?”

However, it should surprise no one that an often very cheap and often mass-produced, battery-powered quartz movement does not give the same sense of appreciation to most luxury watch enthusiasts. So what is it about the Grand Seiko Spring Drive that has everyone so excited?

To understand the excitement, we need to look at why quartz crystals were incorporated into watch mechanisms in the first place. There are clear benefits to using quartz. That is, they oscillate regularly at an incredibly high frequency of 215, or 32,786 Hz. The simple math behind how this works is by constantly dividing the pulse into two, resulting in regular one-second intervals.

This provides unmatched precision compared to mechanical mechanisms. The truth is that even the most precise mechanical watches cannot match quartz in terms of accuracy and reliability.

What makes the Grand Seiko Spring Drive different from a quartz movement?

A traditional, quartz-powered watch contains a battery that emits a charge that makes the quartz crystal vibrate at a frequency of 32,786 Hz. This results in an accuracy of +/- 15 seconds over 30 days. So there is a permissible deviation in accuracy of 15 seconds back or 15 seconds forward per month. Of course, this is provided you keep the watch within a normal temperature range, from 41 degrees Fahrenheit to around 95 degrees Fahrenheit.

In a Grand Seiko movement using Spring Drive, the frequency ratio of the quartz allows the minute hand to glide extremely smoothly. You'll stare at him in amazement for hours.

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How Precise Is a Grand Seiko Spring Drive?

The Grand Seiko Spring Drive has an accuracy of +/- 1 second per day; This is twice as accurate as the finest Rolex Superlative Chronometer, more accurate than a METAS-certified Master Chronometer, and many times more accurate than a COSC-certified Chronometer.

What Grand Seiko did was pure genius; They combined the precision of quartz with the creativity in engineering a traditional mechanical watch. They designed a system that allows a fully mechanical watch mechanism to take advantage of the stability and oscillation frequency of the quartz crystal; While this system operated the mechanism with a small electrical current produced mechanically, it also regulated all of this with an internal circuit, without using any batteries.

How Does Grand Seiko Spring Drive Work?

Instead of the battery used in an ordinary quartz movement, it is the voltage released by the mainspring in the watch that produces a small electric current. This charge is what drives the crystal's high oscillation rate. Most mechanical movements measure the pulse of the movement in VpH, or Vibrations Per Hour; However, the frequency rate of quartz is so high that it is measured in Hz (Hertz), that is, cycles per second.

How Many Vibrations Per Hour (VpH) Does a Quartz Crystal Have?

For example, a high-pulse mechanical movement like the Zenith El Primero has a frequency of 36,000 VpH (vibrations per hour) or 5 Hz, while quartz with a frequency of 32,786 Hz resonates at a rate of32,786 vibrations per second. This corresponds to 118,029,599.999 VpH, that is, the vibration in the watch.

This Integrated Circuit i.e. IC takes care of continuously splitting the high pulse of the crystal and again, all this is done without using even a single battery. This triggers a stepper motor that moves the minute hand, producing one-second increments.

So what exactly regulates the movement of gears? One would think that with something with such a high frequency rate things could get out of control. The magic behind why Spring Drive remains so precise and stable is entirely in the IC and glide wheel.

The Integrated Circuit looks at the speed of the glide wheel, the driving force behind the mechanical gears, and compares it to the oscillator. If it sees that the glide wheel is spinning too fast, it applies a magnetic brake to keep it under control. This is a smart braking mechanism or a cruise control for your caliber, so to speak. Let me say this; Grand Seiko and their Spring Drive are truly something else!

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