Back in 1998, Grand Seiko introduced the Caliber 9S, which marked the start of an entirely new generation of mechanical watch movements for the brand. While Grand Seiko produces a wide assortment of different calibers including its various Spring Drive and 9F Quartz movements, it is the 9S series that sits at the heart of Grand Seiko’s mechanical catalog, and to celebrate the 25th anniversary of the Caliber 9S, Grand Seiko is launching two different limited-edition GMT watches that are inspired by the blue skies above Mount Iwate in Japan. While the Grand Seiko SBGJ275 is based on the GMT models from the brand’s Sport Collection and will be produced as a limited edition of 2,000 pieces, the Grand Seiko SBGM253 is part of its Elegance Collection and will have a smaller production run of 1,700 examples.

Crafted from stainless steel and paired with a matching stainless steel bracelet, the Grand Seiko SBGJ275 is based on the full-size GMT model from the brand’s current Sport Collection, and its case measures 44.2mm in diameter by 14.8mm thick, with 21mm lugs and an overall lug-to-lug profile of 50.6mm. A signed screw-down crown is located on the side of the case at 4 o’clock, and a double-domed sapphire crystal with anti-reflective treatment on its underside surface sits above the dial. With that in mind, the split-color sapphire bezel insert appears in blue and white to compliment the sky-themed colorway of the watch, and rather than featuring a closed caseback like the standard production models, the new SBGJ275 is fitted with a screw-down display caseback, which represents the first time that a mechanical Grand Seiko watch with a water resistance rating of 200 meters has allowed users to see inside and admire its movement.

Best of all, Grand Seiko has successfully resisted the urge to adorn the new SBGJ275’s caseback display window with some type of printed graphic, which means that the clear piece of sapphire is able to fully serve its intended purpose and offer users an unobstructed view of the finely-finished movement that powers the watch. Given that the Grand Seiko SBGJ275 has been released to celebrate the 25th anniversary of the Caliber 9S, the watch is naturally powered by a movement from this series, and driving the hands is the high-beat Cal. 9S86, which offers an accuracy rating of -3/+5 seconds per day and runs at a frequency of 36,00vph (5 Hz) with a power reserve of 55 hours. Grand Seiko movements are always very nicely finished, and the Caliber 9S86 inside the new SBGJ275 is also fitted with a skeletonized titanium oscillating weight that has been treated with an anodic oxidation process to give it a light blue asymmetric finish that complements the dial of the watch.

The dial of the new Grand Seiko Sport Collection GMT SBGJ275 follows the same overall design and layout as the standard-production automatic model, which means that it omits the power reserve indicator that can be found on the various Spring Drive versions to increase the amount of visual balance between its faceted hour markers and framed date window at 4 o’clock. Just like its siblings, the new SBGJ275 has an angled rehaut with a secondary 24-hour scale and a split-color finish, which leaves its rotating bezel available to simultaneously display a third time zone when needed. The asymmetric pattern across the surface of the SBGJ275’s dial is intended to depict the layered sea of clouds that envelops Mount Iwate at daybreak, while the pale blue color has been chosen to highlight the surface pattern and provide the appearance of a dense sea of clouds floating in the sky. Grand Seiko dials almost always look exponentially better in person, and since this one already looks rather promising in the press images, there is a good chance that it will truly be impressive on the wrist.

The other new GMT watch released to celebrate the 25th anniversary of the Caliber 9S is the Grand Seiko SBGM253, which is part of the brand’s Elegance Collection and offers a noticeably dressier appearance compared to its sibling. While the SBGM253 is also crafted from stainless steel and fitted with a matching bracelet, it features a significantly more compact case that measures 39.5mm in diameter by 13.7mm thick, with 19mm lugs and an overall lug-to-lug profile of 46.9mm. Instead of having a bezel with a 24-hour scale, the Grand Seiko SBGM253 receives a simple fixed bezel with a Zaratzu-polished finish, and this surrounds a box-shaped sapphire crystal that has anti-reflective treatment on its underside surface. As the dressier option among this new duo, the SBGM253 only offers 30 meters of water resistance, and rather than being threaded into the middle case, its display-style caseback is secured by six small screws.

Compared to its Sports Collection sibling, the dial fitted to the Grand Seiko SBGM253 offers a less elaborate and more traditional design with a crisp light blue color and a sunray finish that is inspired by the sky as seen from the peak of Mt. Iwate. The overall layout of the dial is shared with other GMT models from the Elegance Collection, with faceted hour markers, a framed date window at 3 o’clock, and a 24-hour scale printed along the interior perimeter of its applied indexes, which appears in dark blue to match its thermally blued GMT hand. Like other models from the Grand Seiko Elegance Collection, the new SBGM253 doesn’t feature any lume on its hands or hour markers, and on both of these new limited-edition models released to celebrate the 25th anniversary of the Caliber 9S, the applied “GS” logo on the dial appears as a contrasting accent in yellow gold.

Despite both being GMT watches that offer independently adjustable local 12-hour hands, the 9S series movement inside the new Grand Seiko Elegance Collection SBGM253 is quite a bit different from the one that can be found inside its Sport Collection sibling. Powering the Grand Seiko SBGM253 is the brand’s Caliber 9S66 automatic GMT movement, which offers an identical accuracy rating as the high-beat Cal. 9S86 that is found inside its Sport Collection sibling, although it operates at a lower frequency of 28,800vph (4 Hz) with a longer power reserve of 72 hours. The skeletonized titanium rotor fitted to the Cal. 9S66 inside the new Grand Seiko GMT SBGM253 showcases the same type of finish that can be found on the rotor of its sibling, although rather than being a pale blue hue, it appears in a vivid dark blue color to compliment the watch’s dial accents and GMT hand.

Despite being very similar conceptually (both models are stainless steel GMT watches that are powered by automatic movements and fitted with blue dials inspired by the sky above Mt. Iwate), the Sport Collection SBGJ275 and the Elegance Collection SBGM253 are ultimately very different timepieces, and this is reflected in the retail prices that accompany them. Given its high-beat movement and more involved case construction, the new Grand Seiko Sport Collection SBGJ275 is naturally going to be more expensive than its dressier sibling, and it has an official retail price of $7,600 USD, while the Elegance Collection SBGM253 costs noticeably less and is priced at $5,600 USD. Additionally, despite being the more expensive model, the Grand Seiko SBGJ275 will be produced as a limited edition of 2,000 examples, while the more attainable SBGM253 will have a smaller production run of 1,700 pieces. For more information on the Grand Seiko Sport Collection SBGJ275 and Elegance Collection SBGM253 Caliber 9S 25th Anniversary Limited Edition GMT watches, please visit the brand’s website.