The Grönefeld One Hertz is the second complicated mechanical timepiece created by Swiss trained, Netherland based watchmaking brothers, Bart and Tim Grönefeld. The movement for this new timepiece, was created completely in-house. The dial indicates hours and minutes on a sub-dial at 2 o’clock.

Power reserve is indicated at 12 o’clock. But what really makes this timepiece standout, is the deadbeat seconds, which is indicated by the large off-centre sub-dial. Independent deadbeat seconds, rotate the dial (independent means the seconds are displayed in the sub-dial) by ticking forward, much like on a traditional quartz movement. Except that this is, of course, a mechanical movement, which really makes it complicated to produce. In fact, this is the world’s first and only mechanical timepiece with independent deadbeat seconds.

Press Release

With the One Hertz’s unique secondary gear train, Tim and Bart Grönefeld have re-positioned the deadbeat seconds complication where it originated, i.e. on the pedestal of high precision.

The quartz-like movement of the large second hand of the One Hertz subtly signals its unique mechanism, invisible to most, but obvious to haute horlogerie aficionados who will appreciate the flawless fine-finishing of the in-house developed calibre G-02.

The One Hertz launches with a subscription-only limited edition of 12 pieces in steel called the “One Hertz 1912″ – 1912 was the year Tim and Bart’s grandfather qualified as a watchmaker.