The Calibre 135 is the movement that defined Zenith’s reputation during the observatory chronometer competition era of the mid-twentieth century, and it remains the most decorated movement the Le Locle Manufacture has ever produced. For the G.F.J. Calibre 135 Double Signed with Naoya Hida & Co., Zenith has partnered with the Japanese independent watchmaker to reinterpret the G.F.J. collection through a design sensibility shaped by decades of close study of that specific movement. Naoya Hida has been drawn to the Calibre 135 since the 1990s, and that history is not incidental to the project. It is the reason this collaboration exists at all. The watch is presented in a 39mm platinum case housing a hand-wound Calibre 135 that beats at 2.5Hz, holds a 72-hour power reserve, incorporates a stop-second mechanism and is COSC certified to plus or minus two seconds per day. The solid silver dial carries all its indications, including the double signature, hand-engraved by master engraver Keisuke Kano and filled with blue Japanese urushi lacquer. The hour and minute hands are CNC-milled from solid gold and hand-polished, while the small seconds hand is heat-treated steel blued to match. Through the sapphire caseback, the movement displays broad Geneva stripes, hand-chamfering and a contemporary dark ruthenium finish with yellow gold accents. Three straps accompany the watch: Himeji Kurozan leather finished with successive layers of urushi lacquer, Wagyu leather prepared by the craftsmen of Kyoto Leather, and a deep indigo denim produced by the Kaihara mill in Fukuyama, Hiroshima. The platinum pin buckle carries the G.F.J. initials. The edition is limited to 10 pieces.