Moritz Grossmann Perpetual Calendar
Glashütte based haute-horlogerie manufactory Moritz Grossmann celebrates its 17th anniversary with a Perpetual Calendar watch.
Traditionally, a perpetual calendar combines a variety of information on a single dial. Arranging this information in an appealing way is a challenge of its own. The Moritz Grossmann PERPETUAL CALENDAR offers a symmetrical and clear dial where all the indicators come together to form a single, harmonious picture.
Both the watch’s appearance and its legibility benefit from the way the date is presented on a ring running around the dial, with a full date scale from 1 to 31 printed on it. To distinguish the date display from the hour and minute hands and keep the face tidy and clear, there is a cup-shaped indicator on the outside that marks the current date by framing it. Another ring further in on the dial has a fine radiant cut to it that bolsters the elegant appearance.
The month and day of the week are displayed on two subsidiary dials left and right of centre, at 3 and 9 o’clock. They are decorated using a refined Azurage technique, just as the small seconds are. This technique involves a circular pattern of ultra-thin grooves which catch the light in an intriguing and appealing way.
Each of these subsidiary dials has a small window at its centre. One of them serves as a leap year indicator, as the hallmark of a perpetual calendar is its knowledge of leap years and indication of the 29th of February every four years. The second small window is a day–night display which makes it easier to link the time with the date when setting the watch.
The 12 o’clock position features a poetic moon phase display where a gleaming mother-of-pearl moon tracks across a dark night’s sky with small, sparkling stars.
The soft glow of the moon is set against a goldstone background which is illuminated by small copper crystals. Together, it is all reminiscent of a starry night’s sky. Correctors are located on the sides of the case for all the displays on the PERPETUAL CALENDAR.
Using them, the date, day of the week, month and moon phase can quickly be set and coordinated. The correctors are recessed subtly into the case and are operated with a special tool that comes with the watch.
The timepiece offers a further special feature in the form of a sum corrector. If the watch goes a few days without being wound, this pusher is all the wearer needs to revise the date since the day-of-week, month and moon phase indicators will all follow automatically.
Beating inside, the newly engineered 101.13 hand-wound calibre is purely a plate movement based on a modified 100.1 movement with a module set on top for the perpetual calendar. Overall, it is an exceedingly complex piece of design that integrates numerous components. The module for the perpetual calendar alone consists of 211 individual parts, and they are complemented by the 190 components in the base movement.
Many of the movement’s details are brand new, including a simpler, optimised stopwork, an integrated manual winder and an escape wheel bearing integrated into the barrel bridge.
Apart from the sophisticated architecture, just the sheer aesthetics of the calibre alone are another key feature. This is because Moritz Grossmann decorates and finishes its movements in accordance with all the rules of traditional haute horlogerie.
The Moritz Grossmann PERPETUAL CALENDAR is making its debut in three variants. Two models sport a rose gold case with slim, lance-shaped hands made of rose gold. The cup-shaped date indicator and hour appliqués are colour-coordinated to perfection.
One of the models features a gleaming silver argenté dial whilst the other has a vibrant anthracite dial.
The third PERPETUAL CALENDAR variant is presented in a platinum case with a dial combining argenté and anthracite colours. The hour appliqués also have a silver colour, and the slender hands are made of blue tempered steel to ensure they are easy to read against the light background.
All three watches are worn on a dark brown alligator leather strap with a prong buckle.
Model: Moritz Grossmann Perpetual Calendar
References
Rose Gold, Argenté: MG-003906
Rose Gold, Anthracite: MG-003907
Platinum, Argenté, Anthracite: MG-003904
Movement
Manufacture calibre 101.13
Manual winding, regulated in five positions
No. of parts: 401 (movement 190/calendar gears 211)
Diameter: 41.0 mm
Height: 13.9 mm
No. of jewels: 37 jewels, including 4 gold chatons, 3 of which are screwed
Escapement: Lever escapement
Oscillator: Shock-absorbed Grossmann balance with 4 inertia screws and 2 poising screws, suspended Nivarox 1 balance spring with No. 80 terminal curve, Gustav Gerstenberger geometry
Balance Diameter: 14.2 mm, frequency: 18,000 semi-oscillations per hour
Power reserve: 42 hours when fully wound
Functions
Hours and minutes, small seconds with stop-second function, date, day of week, month, moon phase, Grossmann manual winder with pusher
Operating elements
Crown in rose gold/platinum to wind the watch and set the time; pusher in rose gold/platinum to start the watch; correctors in rose gold/platinum to set the date, day of week, month and moon phase; sum corrector in rose gold/platinum to correct the date
Case
Three-part, rose gold/platinum
Diameter: 36.4 mm
Height: 8.3 mm
Crystal/display back: Sapphire crystal, antireflective coating on one side
Dial
Argenté, argenté/anthracite, inner ring finished with a radiant cut, subsidiary dials decorated with Azurage, indices in the form of appliqués, goldstone moon phase display, mother-of-pearl moon
Hands
Manually crafted rose gold, polished; manually crafted steel annealed to a blue hue
Strap
Hand-stitched alligator leather with solid prong buckle in rose gold/platinum
Special features
Balance staff with integrated safety roller, location of the impulse pin in the balance (Glashütte style); index adjuster with fine screw; 2/3 plate inspired by historical M. Grossmann pocket watches; frame parts in untreated German silver; raised gold chatons with pan-head screws; stop-second function at safety roller for pulling the crown; hand setting override and start of movement with lateral pusher; gear wheel stopwork with two-teeth backlash
