Introduced in 1998, Grand Seiko's calibre 9S marked the beginning of a new generation of mechanical watchmaking for the manufacture. Developed from scratch with precision and durability at its core, the 9S architecture became the foundation for an expanding family of Grand Seiko mechanical movements, eventually encompassing Hi-Beat calibres, GMTs and more advanced constructions. In 2023, Grand Seiko celebrated the movement family's 25th anniversary with the SBGJ275, a limited-edition Hi-Beat GMT from the Sport Collection.

Limited to 2,000 pieces, the SBGJ275 takes its visual inspiration from the landscape surrounding the Grand Seiko Studio Shizukuishi, where the manufacture's mechanical watches are assembled. Its textured blue dial evokes the sky above Mount Iwate at daybreak, when the mountain can appear above a dense sea of clouds. A blue-and-white sapphire GMT bezel allows three time zones to be followed simultaneously, while the exhibition case back reveals another anniversary detail: a titanium oscillating weight anodised to produce a pale blue finish. Inside is the Hi-Beat calibre 9S86, operating at 36,000 vibrations per hour and combining Grand Seiko's high-frequency mechanical watchmaking with an independently adjustable local-hour GMT display.