Breguet’s Hora Mundi first saw the light of day in 2011 after a previous, simpler GMT version that’s now been largely forgotten. The new Hora Mundi is clearly identifiable at first glance due to its faithfulness to all Breguet’s style codes: a fine guilloche finish on the case and dials, hollow-tip hands, the Breguet signature on the gold dial, and so on. Indeed, it’s to uphold these canons of style that despite its travel complication, the Hora Mundi was designed to be as minimalistic and as clearly readable as possible. There’s no question here of displaying the 24-hour disc in its entirety, or of adding innumerable pushers and correctors to deal with all the various subtleties of world time. The judicious layout features a date window at 12 o’clock, offset by one for the selected city at 6 o’clock. One relatively rare feature is that these two windows aren’t the same shape; the Moon Phase, meanwhile, is located between 3 and 4 o’clock.
The 2011 Hora Mundi comes in a generous diameter of 44 millimetres and is 13 millimetres thick. Originally, the piece was available in red gold or platinum, and had another distinguishing feature: three versions of the dial were available, displaying Europe, Asia or the Americas.
An ingenious movement
The calibre is extremely simple to use: depressing the pusher at 8 o’clock adjusts home and destination time to match the reference city displayed at 6 o’clock. As well as changing the time, this action also adjusts the date where necessary, taking into account whether it’s AM or PM. To achieve this, the single set of hands is linked to a ‘mechanical memory’ that tracks the time being used for both time bands. This means that both home time and the time anywhere else in the world can be set, and then switched between as required.
The first ‘tracked’ date
The date display may look simple enough, but it is in fact quite unusual. It uses a rotating disc that allows three successive dates to be displayed. The day’s date is circled by a retrograde indicator that follows it throughout the day, travelling from left to right across the window. At midnight, the hand supporting the indicator jumps back to denote the date of the new day as it begins.
This is all done without affecting the usual time display; a stop seconds mechanism is used to keep this accurate when setting the time. The distinctive ‘mechanical memory’ is based on a dedicated movement, the Cal. 77F0 from the 777 movement family, protected by four patents and boasting a 55-hour power reserve.
The globetrotter
Five years after the release of its Classique Hora Mundi 5717, Breguet launched the 5727. Instead of a world map, the latter features a central hand-guilloche decoration, making the dial much less busy and therefore even more understated. The Moon Phase is replaced by a 24-hour indicator divided into two zones, each with its own guilloche finish in a nod to Abraham-Louis Breguet’s original dials, in which a specific finish was used for each indication. Indeed, the 5727 has a much more Breguet ethos than its predecessor. It was itself followed in turn by a new version as part of the Marine collection in 2022, the 5557. This once again features a world map on the dial and comes for the first time on a rubber strap.
Breguet Marine Hora Mundi 5557
Case: white or pink gold, sapphire caseback, water resistant to 100m
Dimensions: diameter: 43.9mm; thickness: 13.8mm
Movement: automatic, Breguet 77F1 calibre, inverted straight-line lever escapement, silicon lugs, escapement wheel and flat hairspring, 28,800vph (4Hz), 55-hour power reserve
Functions: hours, minutes, seconds, date, dual time band, day/night indicator
Dial: blue guilloche, gold base
Strap: leather, rubber, or gold, triple strand folding clasp
Launch year: 2022
This year, GMT Magazine and WorldTempus have embarked on an ambitious project: summarising GMT and Worldtimer watches since 2000 in The Millennium Watch Book - Travel Watches, a beautifully laid-out coffee table book. This article is an excerpt of the book. The Millennium Watch Book - Travel Watches is available for preorder in both French and English here.
