If you thought Greubel Forsey would be trending toward more conservative designs after the brand’s first sub-40-mm timepiece, the Balancier Contemporain, was unveiled at SIHH in January, then you thought wrong. Today, one of watchmaking’s leading independent brands is combining two of its most popular and recognized timepieces, the GMT and Quadruple Tourbillon, into one single bold model, the brand-new GMT Quadruple Tourbillon.

Greubel Forsey had to develop an entirely new movement over an approximate three-and-a-half year period to bring these two remarkable timekeeping mechanisms together. The manually-winding movement is comprised of 805 parts with three fast-rotating barrels. The brand has filed for three patents for this new caliber. Just like with the watch’s direct predecessors, a three-dimensional dial and movement architecture is on full display. Starting in the upper-right corner of the dial, the primary timekeeping display (hours/minutes) is the tallest point of the watch itself. On the lower part of the dial, a power-reserve display indicates how much of the 72-hour running autonomy remains; remarkably, the Quadruple Tourbillon GMT boasts the brand’s longest-running power reserve found in its 15-year history. At the traditional 4 o’clock spot, a coaxial small seconds and second time zone display are located, with the second time zone being adjustable in one-hour increments by means of a pusher that is directly flush with the case itself. Between the 8 and 9 o’clock zone is the GMT function that is visible courtesy of the oversize, three-dimensional globe. On either side of the Earth model are the dueling double tourbillons, each featuring an open and transparent construction, secured by black polished bridges and adorned with gold chatons as well as hand-polished beveling and countersinks. The balance uses a Phillips terminal curve.