Running on caliber 9R86, it features a vertical clutch and column wheel design and an accuracy rating of +-15 seconds per month (which extends to the elapsed time), making it the world’s most accurate spring-driven chronograph. In addition to the chronograph feature, which can measure elapsed time up to 12 hours, Grand Seiko also included a GMT complication for even more functionality. Altogether, caliber 9R86 has more than 400 parts, and each movement is hand assembled by the skilled craftsmen and women of the Shinshu Watch Studio. Today, Grand Seiko is unveiling reference SBGC240, the latest addition to their Grand Seiko Spring Drive chronograph lineup and a limited edition honoring Seiko founder Kintaro Hattori and the 140th anniversary of the company he started. Those familiar with Grand Seiko’s chronograph lineup will likely see some notable design changes here. Let us first turn to the bezel. The base of the bezel features a distinct dodecahedron shape, and it’s rendered in 18k yellow gold. The outer section of the bezel is zirconia ceramic. It is worth noting that this is a solid piece of ceramic and not simply an insert. It’s fixed, colored in black, and features a highly-legible tachymeter scale, the latter detail lending to the sporty look of the watch. Another noteworthy change is the redesign of the chronograph pushers. They’ve been scaled down in size, and they’re no longer screw down like they are on references SBGC201, SBGC203, and SBGC205. The goal was to streamline the design without sacrificing any functionality (the case is rated to 10 bar) or ease of use. Like the bezel, the pushers and the crown are done in 18k yellow gold. The case, measuring 43.8mm across and 16.1mm thick, boasts a beautiful mix of finishing. The top surfaces are given a hairline finish, and the sides are polished to a distortion-free reflection only achievable through Grand Seiko’s Zaratsu method. Around back, an exhibition case back shows off the stunning 9R86 caliber. Chronograph functionality is arranged in an incredibly legible way on the dial. A 30-minute register is positioned around two o’clock, a twelve-hour register below that at four, and an active seconds hand is placed at nine. Additionally, there is a power reserve indicator around seven. A GMT hand allows for tracking a second time zone. The dial is black, and it features gold-tone accents throughout. The chronograph second hand is rendered in silver, color-matching the hands on the two chronograph counters. Reference SBGC240 is paired with a five-link stainless steel bracelet featuring a three-fold clasp with push button release. The clasp features an 18k yellow gold emblem marked with “GS.” Additionally, the watch comes with a crocodile strap with gold-tone stitching.