Grand Seiko’s Revolutionary 9SA5 Movement Gets the Stainless Steel Treatment with the SLGH003

Way back in March, when we told you about Grand Seiko’s solid gold SLGH002 with the all new 9SA5 high frequency movement with a Dual Impulse Escapement, a Grand Seiko invention that represents one of the small handful of true innovations in escapement design over the last several generations of watchmaking, we openly speculated about a time in the future when this new movement would make into a watch that was a little more approachable. It’s not that we didn’t love the SLGH002, but a solid gold dress watch that retails for over $40,000 isn’t exactly something you impulse buy. Now, as Grand Seiko’s 60th anniversary year comes to a close, we’re getting our first taste of the 9SA5 movement in a stainless steel watch, much earlier than I’m guessing many observers expected. Let’s take a closer look at the just announced SLGH003.

First things first: while this watch is certainly more attainable than the gold SLGH002, it would be hard to describe it as “affordable” with a straight face. The new SLGH003 will sell for $9,700, and is limited to 1,000 pieces. Given the present rarity of the 9SA5 movement, this watch is likely to be highly sought after by collectors and difficult to acquire, but it’s genuinely great news for fans of the brand that Grand Seiko has already figured out a way to get the 9SA5 into a watch for less than $10,000. These types of technological advancements have a way of trickling down to the consumer level, but it usually happens very slowly. To have this movement in a steel watch so soon after its introduction is a great sign. 

Before we go much further, let’s quickly review what makes the 9SA5 movement so special. Grand Seiko, for decades, has been a leader in high frequency movements. These calibers beat at a faster rate than a standard movement, and are thus capable of keeping more accurate and stable time. The challenge, as always in watchmaking, is efficiency. With a higher beat rate, you squeeze more energy out of the mainspring, resulting in less power, and shorter power reserve times. Bigger barrels can add hours to the power reserve, but it costs you size. Grand Seiko, with the 9SA5, set out to build a movement that operates at a high beat rate, with Grand Seiko accuracy, for up to 80 hours, without making sacrifices in the size department. 

Grand Seiko succeeded here in large part due to the invention of an all new Dual Impulse Escapement, which impulses the balance twice (directly and indirectly) using the same amount of energy that a traditional escapement uses to impulse the balance just once. With the Dual Impulse Escapement, the escape wheel transmits power to the balance directly when it swings in one direction, and indirectly through a traditional pallet fork when swinging in the opposite direction. This makes the 9SA5 significantly more efficient than a traditional high frequency caliber. To make the most out of this saved energy, Grand Seiko was able to fit a second barrel into the caliber without adding significant weight to the movement (thanks in large part to MEMS design principles), allowing for stable timekeeping to +5/-3 seconds per day with 80 hours in the tank. 

So, that’s the movement in a nutshell (for more, be sure to check out our original story on the SLGH002 linked above, as well as this piece on the Grand Seiko’s T0 concept movement, which is inextricably linked to the 9SA5 in some key ways). But what about the SLGH003 as a watch? Grand Seiko, unsurprisingly, has created something special to match the movement inside. The blue dial is a Grand Seiko hallmark at this point, and we’ve seen it appear several times over the course of their 60th anniversary release schedule. The case matches the original gold watch from March, and has been finished with wide Zaratsu polished bevels. It’s interesting to consider how the 44GS inspired case changes in character from gold to steel. The earlier SLGH002 had an appearance that was refined and classic, but something about the steel SLGH003 gives the same design a more imposing feel. While this watch could certainly work as a dress piece, as most Grand Seikos that are not explicitly part of their Sport Collection can, it really feels more like an old fashioned everyday, every situation kind of timepiece. At 40mm in diameter with a thickness of 11.7mm, it’s definitely versatile in terms of size, and it has 100 meters of water resistance to boot. 

The bracelet has also been reworked and is now more substantial, and features Grand Seiko’s folding clasp with a gold “GS” signature. This, along with the gradient blue dial, is a reminder that the watch is limited in production, and an anniversary piece. Also notable is that the movement can be seen through the sapphire caseback. And when I say “seen,” I really mean it. Grand Seiko has taken some fair criticism as of late for hiding their movements behind graphics featuring their own logos. On the SLGH003 the logo is still there, but it’s faint, and doesn’t seem to get in the way of observing the 9SA5. Not only that, but the rotor of the 9SA5 is skeletonized, offering a view of the entire caliber. For this movement, it’s worth it. 

The new SLGH003 will be available in December through select Grand Seiko retailers and Grand Seiko boutiques. More information here.