The Mechanics of Time: Inside the Bremont Terra Nova Jumping Hour 1776
Mechanical watchmaking has always found elegant ways to make time feel different, but few functions achieve that quite like the jumping hour. At first glance, it appears almost digital, displaying the hour through a simple aperture rather than a traditional hand. Beneath the dial, however, lies one of horology's most ingenious mechanical systems.
To commemorate the 250th anniversary of the United States, Bremont has introduced the Terra Nova Jumping Hour 1776 - a limited edition of just 250 pieces. Powered by the exclusive BC634AH calibre developed for Bremont with Sellita, this jumping hour tool watch combines the heritage of the historic Montre à Guichet design and the precision engineering that defines modern Bremont watchmaking.
What is a Jumping Hour Watch
A jump hour watch displays the hour through a dedicated window rather than with a conventional hand. Unlike a traditional mechanical watch, where the hour hand moves continuously around the dial, a jump hour watch keeps the hour fixed until it changes - or “jumps” - instantaneously at exactly sixty minutes.
The complication first appeared during the 19th century, when a jumping hour timepiece was created around 1830 by French watchmaker Antoine Blondeau for King Louis Philippe I. The watch then enjoyed widespread popularity throughout the Art Deco era in the early 20th century, when the clean windowed display of the Montre à Guichet offered a strikingly modern alternative to traditional watch dials. Today, collectors continue to value the jump hour watch because it combines exceptional legibility while showcasing genuine mechanical ingenuity.
How does a jumping hour mechanism work?
The apparent simplicity of a jump hour watch display disguises an intricate mechanical process. Over the course of sixty minutes, the movement gradually stores energy within a dedicated spring. Rather than driving the hour display continuously, that energy is held under controlled tension until the precise moment it is needed. At the top of the hour, a carefully engineered release mechanism allows the stored force to rotate the roulette-style hour disc in under one tenth of a second.
Generating that instantaneous movement requires significantly more torque than a conventional hour hand. The mechanism must overcome the inertia of the hour disc while ensuring it indexes perfectly every time. It is this careful balance of stored energy, precision gearing and controlled release that makes a jumping hour one of watchmaking's most admired watch complications.
Just as importantly, eliminating the traditional hour hand for a cleaner disc display allows the hour aperture to become the focal point of the dial. This also creates the balanced symmetry that made the original Montre à Guichet so distinctive, and it’s one of the reasons the jump hour watch remains such a sought-after watch complication among collectors.
Engineering the Terra Nova Jumping Hour 1776 watch
The Terra Nova Jumping Hour 1776 pairs this historic part of watchmaking history with Bremont's modern engineering philosophy. Developed exclusively with Sellita, the BC634AH calibre operates at 28,800 vibrations per hour (4Hz) while delivering a 56-hour power reserve. Designed specifically to generate the high torque demanded by a jumping hour display, it enables the hour disc to change cleanly in less than a tenth of a second.
The jump hour watch itself reflects the purposeful character of the Terra Nova collection, drawing inspiration from the military pocket watches of the early 20th century. Its 40.5mm cushion-shaped case is crafted from corrosion-resistant 904L stainless steel, with a slim profile and shortened lugs that result in a thoroughly modern, durable and resilient field watch that can stand fast and stay functional through all of the land's elements.
Meanwhile, the deep blue grained dial features a 1776 inscription, silver star minute track and bold red accents that pay homage to the USA’s heritage. This is strengthened when the watch is turned over, where the caseback reveals an engraved eagle soaring over a stars-and-stripes motif, reinforcing the significance of this limited edition.
Discover the Terra Nova Jumping Hour 1776
Limited to just 250 pieces, the Terra Nova Jumping Hour 1776 is not just a celebration of America’s historic 250 year milestone of independence, but also one of mechanical innovation and purposeful design. It proves that some of watchmaking's oldest ideas remain among its most compelling.
Explore the 1776 collection with the 904L stainless steel bracelet and the blue textured leather strap, and browse the wider range of Terra Nova Jumping Hour watches to discover the next evolution of Bremont’s modern field watch engineering.
