Greubel Forsey may have just broken their own mold with their first sports luxury watch (emphasis on luxury), but now they’re returning to something familiar: a perpetual calendar, or in their own terms, the Quantieme Perpetual (QP), this time with the addition of the equation of time.
The equation of time, for those not versed in astrology, calculates the difference between mean solar time — the theoretical position of the sun if its motion across the sky remained constant — and apparent solar time, which is what it actually appears to be. Essentially, it’s the difference between a sundial and a clock.
It’s as useful as the moon phases, since no one needs to know true solar time; we just account for seasonal variations and keep to a standard 24-hour clock. But it’s still an impressive feat, and on the QP à Équation, it’s a key reason to flip the watch over and look at the caseback. You simply read the number where the blue or red line (indicating – or + minutes) intersects the white scale. Letters indicate months; colors indicate seasons, and semicircles indicate the spring equinoxes.
Below it, you can see what Greubel Forsey calls a “mechanical computer,” a patented mechanical maze of cams and moving fingers that calculates the QP and equation of time features.
The equation of time sits next to the year indicator, which means two pieces of information you don’t need are hidden away on the back. The rest of the calendar—day, date, and month—can all be read on the second dial side, aligned with one another. The leap year indicator is right next to it at 6 o’clock, which means it’s a surprisingly oriental way to read on a perpetual calendar despite the large number of indications.
The centrally-running hours and minutes isolate the seconds hand on a subdial at 7.30, slightly truncated by Greubel Forsey’s signature, 25-degree tilted 24-second tourbillon and the 24-hour day/night indicator that sits just below it.
The final highlight is the power reserve indicator at 2.30, essential for a watch you never want to see power out. Even though the bidirectional crown makes things easier, setting the perpetual calendar is an unavoidable pain.
All of this is surrounded by a 43.5mm rose gold case that’s understandably sturdy, but not too large considering everything it packs in. Despite the added complications, it’s actually the same size as a standard QP. Paired with a chocolate brown dial, this is Greubel Forsey’s prettiest piece to date. Hopefully we’ll see it in the flesh soon.
Price and specifications:
Model name: Greubel Forsey QP à Équation
Case/dial: 43.5mm diameter x 16mm thickness, 5N red gold
Water resistance: 30m
Movement: Manual winding
Functions: Hours and minutes, small seconds, 24-second tourbillon, 24 hours, power reserve, perpetual calendar base display with disc, mode selector display, equation of time display and year display on case back
Frequency: 21,600 vph (3 Hz)
Power reserve: 72 hours
Strap: Brown alligator leather with red gold folding clasp
Price: CHF 670,000
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