Grand Seiko Returns to Mt. Iwate With New SLGH027 In Evolution 9 Collection

Grand Seiko is expanding its Evolution 9 collection this week with a new reference that draws inspiration from Japan’s Mt. Iwate from a perspective we’ve not witnessed before. The watch is the Reference SLGH027, featuring a Zaratsu-polished case, designed in the lineage of the 44GS, housing the brand’s dual-impulse Caliber 9SA5 automatic movement. All that is to say nothing of the truly stunning dial, whose textured surface has been crafted in a way that evokes the view of Mt. Iwate as viewed from above. The result falls in line with what we’ve come to expect from Grand Seiko in recent years — which is to say, quite lovely. 

Grand Seiko produces its watches in northern Japan’s Studio Shizukuishi, an area that is often used as a source of aesthetic inspiration by the brand. We’ve seen exquisite textures and colors emerge from the natural surroundings of this region, and others in Japan, which bring something of a personal touch to the watches being produced. Not far from the studio sits Mt. Iwate, which is a stratovolcano complex in the western Iwate Prefecture. The beauty of the mountain first inspired a Grand Seiko watch — the reference SBGL001 — back in 2006. With the SLGH027, we’re getting a new perspective of the terrain as seen from above. 

The dial of the SLGH027 features a dynamic texture radiating from the center, set within a clean, light blue color. The dial feels organic in nature, with no visible repeating patterns. The design is meant to mimic the rough landscape leading up to a peak, and when viewed with this knowledge, it does exactly that. Viewed without that context, the dial still presents as visually breathtaking, crafted in a fashion that is unique to Grand Seiko. The dial is subtle, but powerful. Also present are large, applied hour markers, a framed date aperture at 3 o’clock, and a set of rather wide hands. It’s a design language we’ve seen for several years in the Evolution 9 collection, and while these components have their own strong personality, they never seem to interfere with the dial itself. 

Not content to play second fiddle, the case itself packs plenty of details to enjoy. Sized at 40mm in diameter, the case is constructed from Ever-Brilliant Stainless Steel, or what Grand Seiko calls “the world’s most corrosion-resistant stainless steel.” Grand Seiko’s watchmakers have honed its cases over the years, placing a priority on ergonomics, which we see reflected here in the form of a slightly bowed mid case. On this note, the lug width is a wide 22mm, which sets a broad base for equal dispersion of heft on the wrist. The case features a mix of brushed and Zaratsu-polished surfaces, which provides a sharp, crisp contrast.

At work inside we find Grand Seiko’s 9SA5 automatic movement, which is visible through an exhibition caseback. There is an impressive level of finishing on display here, and the overall design of the movement is quite captivating as well. There is a dual-impulse escapement at its heart, providing a direct power transfer from the escape wheel to the balance, making the flow of power from the mainspring all the more efficient. The mean daily rate of accuracy is within +5 to -3 seconds per day, and it looks pretty cool ticking away under the full balance bridge. It’s also worth noting that this is a high-beat, 36,000-VPH movement, and it offers 80 hours of power reserve on tap. 

The Grand Seiko Evolution 9 Reference SLGH027 will be available from May of 2025, and will be limited to just 1,200 units produced. Pricing is set at $10,500.