Launched in 2026, the Zenith G.F.J. Calibre 135 Double Signed with Naoya Hida & Co. 40.1865-2.0135/01.C220 marks the debut of Zenith's Double Signed Program, limited to just 10 units. This model combines Zenith's contemporary G.F.J. framework with the design aesthetic of the Japanese artisan watchmaker Naoya Hida & Co. At its core lies the re-envisioned Calibre 135, a historically important chronometer that rejoined the lineup in 2025 to celebrate the brand's 160th anniversary. The watch features a platinum case that measures 39.15 mm in diameter, is 10.5 mm thick, and spans 45.75 mm from lug to lug, encasing a solid silver dial inspired by Hida's subtle mid-century design principles, particularly reflecting aspects of the NH Type 2A. Each detail of the dial, including the signatures of both Zenith and Naoya Hida & Co., is hand-engraved by master engraver Keisuke Kano and filled with blue Japanese urushi lacquer. This meticulous process extends to the hour markers, providing a structured visual without reliance on applied decorations. The dial maintains a minimalist layout, featuring central hours and minutes along with a small seconds display located at the 6 o'clock position. Material considerations are equally important for the hands, with the hour and minute hands crafted from solid gold and intricately CNC-machined and polished, while the small seconds hand is crafted from steel and given a heat-blued finish. The overall dial aesthetic emphasizes engraving, lacquer contrast, and precision in proportions, seamlessly incorporating its double signature into the dial itself. Viewable through a sapphire case back, the hand-wound Calibre 135 boasts a modern specification, operating at 18,000 vibrations per hour (2.5 Hz) with a 72-hour power reserve. It features a large variable-inertia balance, a Breguet overcoil, a double arrow-shaped regulator designed by Charles Fleck, jewel settings for the balance staff that are spring-mounted, and a stop-seconds function. This movement is COSC-certified, ensuring it operates within a regulation of +/-2 seconds per day and features refined finishes including broad Côtes de Genève, hand-chamfered edges, a dark ruthenium coating, and yellow gold-tinged markings. The watch comes with three different straps: Himeji Kurozan leather, Wagyu leather produced in Kyoto, and deep indigo non-stretch denim from Kaihara. It is also equipped with a platinum pin buckle engraved with the initials G.F.J., and offers water resistance up to 5 ATM.