Grand Seiko Spring Drive Caliber 9RA5

Earlier this year, Seiko announced a new spring drive movement intended to mark a new beginning for the brand. And with this new Spring Drive caliber is a great way to celebrate their 60th anniversary. Time to have a closer look at the Spring Drive 9RA5.

Grand Seiko was born from a simple and ambitious aim, simply to create the best watches possible. With a small selection of Seiko’s top watchmakers put to work in the late ‘50s, the first Grand Seiko was launched in December 1960. With numerology being very important, in Japan, the number 60 marks a moment of new energy and rebirth.

Grand Seiko 60th Anniversary

Among a selection of special edition watches celebrating this milestone, the brand’s movement lineup got another addition. While traditional watchmaking concerns itself with purely mechanical calibers, Grand Seiko took a different direction following the advent of quartz technology. Lines were drawn in the sand elsewhere, but not at Grand Seiko. The fusion of quartz accuracy with the emotional power of mechanical watchmaking and hand-finishing was born with the development of the Spring Drive movement in the early ‘80s. It took a whopping twenty years before this type of movement was ready for commercial production. But now, in 2020, Seiko takes the Spring Drive to the next level.

Spring Drive 9RA5

More power, a thinner body, and added precision describe the new 9RA5 caliber well. While the first Spring Drive movements already had impressive specs, these have been lifted to a new level. Back in 1999 when the combination of mechanical and quartz technology first merged, it already had a stunning precision of up to one-second deviation per day.

Over time this precision increased up to ± 15 seconds per month. With the launch of the 9RA5 the accuracy significantly improved by 33% to only ±10 seconds deviation per month at the most. This is always a good note to make, as these mentioned numbers are the maximum. Often these watches run much more precisely.

Caliber 9RA5

The new caliber was first presented in a professional diver, which found favor with many of our readers (and even managed to take down the mighty Rolex Sea-Dweller in one of our Sunday Morning Showdowns). The new Spring Drive 9RA5 comes with impressive specs. To do a recap, it is thinner, packs more power and the precision has also significantly increased. Comparing this new caliber to the mainstay 9R6 caliber you get a precision of up to 10 seconds compared to 15 seconds for the 9R6. The power reserve has increased by 60% thanks to the incorporation of a double-barrel construction. And the thickness has gone down from 5.8mm to only 5.

Clearly, Grand Seiko has put a lot of effort into creating the next level of watchmaking. As the brand already mentioned, the number 60 marks the re-birth, and this enhanced level of performance can be seen as a similar reenergizing of the brand’s portfolio. Due to the redesign, the stem and crown sit further towards the back of the case. This creates a lower center of gravity which also makes watches toting this movement wear more comfortable on the wrist. 

Offset Magic Lever

Thanks to the re-design and re-positioning of the Magic Lever it was possible to create a thinner profile for this caliber. This Magic Lever was already developed in-house back in 1959. It uses the energy which is created by the bi-directional oscillating weight. This boosts the efficiency of the automatic winding system. By moving it away from the center of the movement, it allows for a reduction of the total thickness. And the best thing is that this change of position doesn’t take away any of the effectiveness of this system. 

With the redesign, added barrel, and re-positioning of the Magic Lever, Seiko delivers a new standard in Spring Drive calibers. Yet this slimming down doesn’t mean that it has lost any rigidness. On the contrary even! Due to the use of a one-piece centre bridge, the 9RA5 also packs enhanced stiffness and shock resistance. It meets the ISO standards for dive watches.

Different sized barrels

What you notice right away about the dual barrel construction is that they differ in size. Seiko took this unusual approach to achieve a power reserve of up to 120 hours, or 5 days, in the limited available space of the movement. Using this construction they deliver the required torque.

This new movement uses highly stable quartz oscillators. These oscillators have been put through a three-month aging process. This ensures their inertness. Additionally, this movement utilizes a brand new IC system. On top of that, Spring Drive uses a temperature sensor for the first time. Much higher precision is achieved by measuring the temperature inside the movement and compensating for any subsequent performance fluctuations. 

All combined, the Spring Drive Caliber 9RA5 certainly marks a new era for hybrid movements. Make sure to check out the official Grand Seiko website to learn about all the Spring Drive technique in detail.