Quick Take

This is the latest example of Greubel Forsey's GMT complication, which was the first GMT watch from the small-batch, extremely high touch tourbillon and chronometry specialists. It debuted in 2013, and it combines a 24 second inclined tourbillon, which is tilted at 25, with a very beautiful spherical model of the Earth which rotates once every 24 hours, and which is driven by the same gearing that drives the GMT complication on the back of the watch. This newest and very spectacular version of the Greubel Forsey GMT combines two double tourbillons with the GMT complication.
The two double tourbillons are based on the original Greubel Forsey Double Tourbillon 30; each consists of two nested tourbillon cages, and both are linked with Greubel Forsey's Spherical Differential, which produces a single average rate for the two oscillator systems. The efficacy of a tourbillon in a wristwatch, in Greubel Forsey's view, is improved when the oscillator systems are constructed so as to prevent them from ever being in any of the positions in which errors of poise are most exaggerated. The watch shows the time in two separate time zones on two dials, and the rotating Earth provides a 24 hour universal time display as well. The case has a sapphire window located adjacent to the globe, which allows the wearer to enjoy a view of the Equator and Southern Hemispheres as well.
Initial Thoughts

Any watch from Greubel Forsey is intended to be interesting on a number of different levels. They are an example of horology as an art form pursued without consideration for time or expense, but they are also deeply appealing to those with an interest in the history of chronometry as a technical pursuit and are especially rewarding to anyone who has a fascination with how various wathmakers from Breguet onwards, have grappled with the tourbillon as a potential ally in improving rate stability.*
Then, too, they are also examples of the craft of watch movement finishing as it can be practiced at the highest level. The screws alone are a kind of museum of high-end finishing techniques, and Greubel Forsey's combination of top level finishing in both the Swiss-French and British idioms, adds to the distinctiveness and character of each timepiece. This sort of thing doesn't come cheaply, nor should it, and the expense of Greubel Forsey watches can sometimes cloud the ability of someone encountering them for the first time, and especially only in photographs, to appreciate what the company is after. But they remain, if difficult to see in person and sometimes forbiddingly difficult to understand, remarkable in every incarnation (if you ask me).
I was lucky enough (insanely lucky enough) to spend a Week On The Wrist with a GMT not long ago and ended the week quite thoroughly in love; I imagine that on a personal level, I'm going to find this one just as irresistible. The addition of the two double tourbillon systems makes this watch a bit of a window into both Greubel Forsey's present and past, and if you like watches that have about as much in common with the average wristwatch as the battleship Iowa has to do with a rubber duck, you might find getting to know this timepiece a very rewarding experience indeed.*
The Basics

Brand: Greubel Forsey
Model: Quadruple Tourbillon GMT
Diameter: 46.50mm
Thickness: 17.45mm
Case Material: White gold; sapphire crystals front and back with lateral sapphire window
Dial: Multi-level in gold, anthracite color
Indexes: Applied gold
Strap/Bracelet: Hand-sewn alligator strap, white gold buckle
The Movement

Functions: Local and home time; universal time indication
Diameter: 39.50mm
Thickness: 13mm
Power Reserve: 72 hours
Winding: Hand-wound
Frequency: 3 Hz (21,600 vph)
Jewels: 84 (train jewels olive shape in gold chatons)
Additional Details: Two double tourbillons; outer cage rotates once per four minutes; inner cage inclined 30 rotating once per minute. Two 10.70mm free sprung adjustable mass balances with Phillips overcoil balance springs. Mainplate and bridges nickel silver.
Pricing & Availability

Price: $820,000
Availability: Not yet announced for U.S. market
Limited Edition: Yes, 66 pieces total worldwide; first run of 11 pieces in white gold.
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