Grand Seiko SBGA427 Review – Heading into “Sōkō”

Fall is my favorite season. There’s something beautiful about the sound of crunchy leaves on the ground and the excuse to add pumpkin and cinnamon into every recipe. It’s also a time when a subtle yet captivating palette comes to life, often filled with oranges, rust and deep red. But when autumn comes near its end, there are other tones that we often don’t even notice. These include the delicate silvers of frost and the muted green tones of fading leaves. It’s this nuanced spectrum of colors and textures that Grand Seiko beautifully brings to life in their Heritage SBGA427 watch, a watch I have been excited to get hands-on with for quite some time now.

Grand Seiko’s Seasons Collection

If you haven’t already checked out Grand Seiko’s Seasons collection, I urge you to do so. The Japanese watch brand has managed to capture the essence of Japan’s twenty-four “sekki” in a range of dial designs. “Sekki” basically describes the different markers of the changing seasons throughout the year. 

Whereas we simply describe them as spring, summer, fall, and winter, the Japanese have a more poetic way of watching the journey of nature, whether it’s the exact moment spring awakens, known as “risshun”, or the first days of winter known as “daikan”. It’s a collection I’m incredibly fond of. There’s something really beautiful about the way Grand Seiko tells the story of the seasons and captures the look and feel of the weather and views through unique dial colors and textures. 

The collection originally debuted in 2019, introducing four watches that represented one of Japan’s twenty four sekki. These included the Grand Seiko SBGA413, named Shunbun, acting as a tribute to Japan’s cherry blossom season, and model SBGH271, known as Rikka, which honored the moment spring turns to summer. There was also SBGH273, or Shubun, to celebrate the autumnal equinox, and finally SBGA415, named Taisetsu, portraying the serene beauty of winter’s deep snowfall. 

Then, in 2020, Grand Seiko expanded the collection further with two special editions exclusive to the United States. One of these is the very watch I’m reviewing today, the Grand Seiko Heritage SBGA427, also known as “Soko”. This particular model celebrates the very end of autumn when the classic warm oranges of the autumn season begin to turn gray and silver as frost starts to embrace the forest.

A 62GS-Inspired Case

While the original Grand Seiko Seasons models from 2019 were a bit on the large side for my wrist—although I’d still wear them if I was feeling brave —the Grand Seiko Heritage SBGA427 feels a lot more comfortable and wearable, especially if your wrists are on the smaller side. The difference might seem subtle, but it makes a noticeable impact. This model is slightly more refined at 39mm in width and just 12.3mm in height, compared to the previous 40mm models with their 13mm height. It’s also worth noting the slightly shorter lug-to-lug distance of 46.8mm, versus the 47.0mm of the older editions.

Like before, the Grand Seiko SBGA427 pays homage to the historical 62GS, Grand Seiko’s first automatic watch released in 1967. Known for its striking mirrored, multi-sided case and bezel-free design, the 62GS was famous for its Zaratsu-polished finish, giving it an organic, almost ethereal feel. The SBGA427 mirrors this legacy with its own sleek and soft profile that beautifully hugs the wrist.

Crafted from stainless steel with both satin and polished finishes, the watch’s polished surfaces are achieved through Grand Seiko’s intricate Zaratsu technique. This process involves meticulously polishing the stainless steel against a spinning tinplate—a craft that takes around three years to master. While Zaratsu is often used on smaller components, it’s impressive to see it applied to the entire case, resulting in a finish that captures the light beautifully. 

The Grand Seiko Heritage “Soko” SBGA427 watch features a screw-down crown at 3 o’clock, knurled for easy grip, and offers 100 meters of water resistance, underscoring its sporty design. The case back is also screwed down and includes a sapphire crystal window to showcase the Spring Drive movement inside. Above the dial, another piece of sapphire crystal is added, this time a dual-curved piece treated to anti-reflective coating on the inner surface to enhance readability in various lighting conditions.

Dial

Before we get into the details of the Grand Seiko Heritage SBGA427’s dial, I mentioned that there were in fact two special editions launched in 2020 exclusive to the US market. Both these models bear the nickname “Soko”, translating to “frost descends” to represent the end of autumn when the first frost touches the forest. Although named the same, their dials offer distinct variations. 

Model SBGA429, the sibling to today’s Grand Seiko Heritage SBGA427, features a darker gray dial reminiscent of the shadows cast by bamboo at autumn’s end. In contrast, the SBGA427 showcases a light silver dial that represents the fleeting breaks of light in the forest of Arashiyama. Both displays exhibit a vertical grained pattern and touches of green, reflecting the diverse hues of bamboo stalks. 

The vertical satin-brushed texture of the surface cleverly emulates the tall, slender bamboo trees and creates a dynamic display that shifts in color depending on the light and angle. The dial of the Grand Seiko Heritage SBGA427 transitions from a light silver to a slightly darker gray, and in some cases, even displays a soft pale blue in certain lighting. 

For a brilliant touch of contrast, the Grand Seiko Heritage “Soko” SBGA427 watch uses emerald green for the seconds hand, power reserve hand, and the movement lettering at 6 o’clock. The rest of the dial features silvered elements, including the sharply faceted hour and minute hands, indices, and date window border, all meticulously hand-finished with diamond-tipped milling tools to mirror the Zaratsu-polished case’s high shine. The only additional hint of color is the subtle gold on the “GS” logo at 6 o’clock, positioned above the black “Grand Seiko” text.

Movement

The Grand Seiko Heritage SBGA427 is powered by the well-known Caliber 9R65 movement, a standout Spring Drive movement made in-house by the Japanese watchmaker. Unlike traditional mechanical movements that rely on a balance wheel and escapement, Spring Drive movements combine the best of both mechanical and quartz watchmaking. 

It uses a traditional mainspring for power, but instead of a conventional escapement, it features a unique glide wheel and a quartz crystal to regulate timekeeping. This allows for a sweeping seconds hand that moves in a completely smooth, continuous motion without any of the jerky beats or stutters you might see in other watches.

It arrives with a generous 72-hour power reserve, which you can easily track on the power reserve indicator on the dial front, and an accuracy of +/- 15 seconds per month or +/- 1 second per day. It really is a technical feat, combining the reliability of quartz with the charm of mechanical movements. The 30-jewel movement is visible through the exhibition case back, showcasing beautiful decoration, including striped plates and an oscillating rotor.

Straps

The design arrives on a classic three-link bracelet with a staggered link alignment for a modern, sporty look. Like the case, the bracelet is beautifully finished with polished outer flanks with their own mirror-like finish and top surfaces that are satin-brushed. It’s a pleasing set of contrasts that blends well with the case, almost making it seem like one solid piece of stainless steel. 

While the bracelet doesn’t include micro-adjustments, it does come with half links secured by screws, which allows for some flexibility in achieving a more precise fit. The single-fold clasp is finished with both polished and satin touches and features the GS logo in relief. It also employs a twin trigger release for added security and ease of use. 

One notable aspect is the 19mm lug width, which is somewhat an uncommon sight in the world of watches, so finding an alternative strap or two might be a little tricky. However, that said, it does have drilled lugs, so swapping out straps is made nice and straightforward if you’re up for a change. Speaking of straps, the watch includes a factory strap as part of the package. This strap features a crocodile pattern with green stitching that perfectly complements the green details on the dial. This strap is finished with its own stainless steel deployment buckle. 

On-Wrist Experience 

For me, the Grand Seiko Heritage “Soko” SBGA427 is the perfect fusion of a dress watch and a sports watch. Its dimensions make it incredibly versatile and wearable. With a diameter of 39mm and a lug-to-lug measurement of 46.8mm (50mm if you include the male end links), it sits comfortably on wrists as small as five-and-a-half inches and looks just as elegant on those above seven inches.

The design strikes a fantastic balance between sophistication and durability. Its elegant case finishing and textured dial add a formal touch, while its 100-meter water resistance and robust build make it resilient enough for daily wear. Whether you’re heading to a board meeting, enjoying a night out, or embarking on an outdoor adventure, this timepiece will no doubt transition seamlessly through all these scenarios.

I’d describe the Grand Seiko Heritage SBGA427 as a democratic watch; it suits a broad range of wrist sizes and occasions. If you have a wrist size up to 7 inches, you’ll find it an excellent fit. However, if your wrist is larger than 7.5 inches, you might find it on the smaller side—unless you prefer that kind of style. For those seeking a high-end, premium watch that’s versatile enough to wear every day, this watch is a great choice. 

Price & Availability

The Grand Seiko Heritage “Soko” SBGA427 watch retails brand new for $5,000 at authorized Grand Seiko retailers like Exquisite Timepieces. You might also be able to find it on second-hand websites for a little cheaper if needed, although, at the time of writing this, it wasn’t an easy one to find pre-owned. Those that I could find seemed to be advertised for around $3,500 and $4,000. 

The watch is marked as a special edition, which means that although it’s not limited to a specific set of numbers, it will only be available for a specific duration. For now, it remains a permanent addition to the Japanese brand’s portfolio, but as for how long that will be the case is hard to say.

Conclusion

You hear all the time about how Grand Seiko is dedicated to handcrafting their watches, with hand finishing used both inside and out. But it’s not until you experience one up close that you truly appreciate the craftsmanship. 

The Grand Seiko Heritage “Soko” SBGA427 is a stunning example of this commitment. Its beauty isn’t just something you talk about; it’s something you feel on your wrist. From the exquisite dial finishing to the overall case design and Zaratsu polishing, every detail is executed to perfection—something you’d expect from Grand Seiko, but it’s always a joy to see in person. Even though I’ve worn numerous Grand Seiko watches, each time I put one on, including this model, I’m reminded of why I’ll never tire of them.