Now, it is ceding this rank to the Ref. 6300: With 20 complications, among them five chiming functions, and a double-face case with a patented reversing mechanism, it is one of the most complicated wristwatches of our era and with certainty also the world's greatest mechanical strikework marvel for the wrist.

In October 2014, on the occasion of the manufacture's 175th anniversary, Patek Philippe presented a suite of limited-edition commemorative timepieces. The most spectacular one was the Grandmaster Chime Ref. 5175. As the manufacture's first wristwatch with a Grande and a Petite Sonnerie, it was crafted in a limited edition of seven pieces, each one with a gold case decorated with stunning, manually executed engravings on all sides. Six of these watches were sold to collectors and aficionados, and the seventh one can soon be admired at the Patek Philippe Museum.

However, to keep its inner cosmos – the caliber GS AL 36-750 QIS FUS IRM – alive, it will henceforth strike the time, the date, and a settable alarm in the Grandmaster Chime Ref. 6300. With a new and distinctive design, it is the most complicated and also the first wristwatch with a Grande Sonnerie in the regular Patek Philippe collection. This timepiece was created to be used on a daily basis. Because production is limited due to its extreme complexity, the Ref. 6300 will remain a rarity for all time.

Extremely complicated, very simple, and highly sonorous

The Grandmaster Chime Ref. 6300 is one of the most complicated watches in the world. Not only because of its 20 complications, but also because of the nature of its horological challenges, among them six patented innovations. Moreover, it is a double-face wristwatch that can be worn with either dial facing up: the one that focuses on the time and the sonnerie, and the other that is dedicated to the full instantaneous perpetual calendar. Reversing the face is very convenient thanks to an ingenious mechanism between the lugs. It is easy to operate and securely locks the case in the selected position. The most important information, such as the time and the date, is displayed on both dials. User- friendliness is guaranteed by intelligent backup mechanisms that largely prevent inadvertent manipulations and thus reliably protect the highly complex movement with its countless tiny parts.

Each caliber consists of 1,366 parts and each case of 214 separate parts, bringing the total number of components for each Grandmaster Chime to 1,580.

The sound makes the supercomplication

The array of acoustic complications includes a Grande and a Petite Sonnerie, a minute repeater, an acoustic alarm with the indication of the preset alarm time, and a date repeater that strikes the date on demand. The time chimes are struck on three gongs, producing a clear, voluminous, and easily perceptible sound that has become a Patek Philippe trademark.

Grande and Petite Sonnerie

The Grande and Petite Sonnerie are functions that automatically strike the time every quarter hour: the hour count at the top of every hour and then the hour count followed by the quarter-hour count on every quarter (Grande Sonnerie) or just the quarter-hour count without the hours (Petite Sonnerie). A separate double strikework spring barrel with a power reserve of 30 hours assures that these time strikes can be executed for a whole day without requiring the watch to be rewound in shorter intervals. Remarkably, this was accomplished even though the quarter-hours are sounded not on two but instead on three gongs with different triple tone sequences. This requires 50 percent more energy for each quarter-hour strike.

Minute repeater, alarm, and date repeater

The double strikework barrel also delivers the energy for the minute repeater, which on demand strikes the hours and quarter-hours as well as the minutes that have elapsed since the last quarter-hour. Connoisseurs automatically associate the clarity and volume of the sounds with Patek Philippe. The alarm strikes the alarm time by reproducing the complete tone sequence of the minute repeater, with exactly the same sound quality. This is a function never before integrated in a mechanical wristwatch. The patented date repeater is all new as well. It is triggered with a pusher in the case flank. It sounds ten-day intervals with a double high-low strike and the remaining days with a high strike: the 23rd of a month is indicated with a ding-dong ding-dong followed by ding-ding-ding.

Instantaneous perpetual calendar

The dial of the perpetual calendar features four subdials with analog displays grouped around the four- digit year display in the middle. The month is indicated at 3 o'clock, the date and leap-year cycle at 6 o'clock and the day of the week at 9 o'clock. The time of day appears at 12 o'clock on the 24-hour and 60-minute subdial. With the exception of the four-digit year, the calendar displays switch instantaneously and concurrently, so that the information for the date repeater is complete and unambiguous even around midnight. Thanks to a patented mechanism, the four-digit year display can easily be incremented or decremented with two correction push pieces in the case flank.

Local time and second time zone

When the crown of the watch points to the right, the owner sees the dial that indicates local time as well as the time in a second time zone together with a day/night indication. The dial also features the power-reserve indicators for the movement and strikework barrels, the position of the winding crown (winding, alarm setting, handsetting), the selection of the strikework mode (Grande Sonnerie, Petite Sonnerie, or Silence), a bell-shaped aperture for the alarm ON/OFF display and a small square window for the strikework isolator (disabled/enabled) display. On the 24-hour dial at 12 o'clock, the desired alarm time can be set in quarter-hour steps. The scale for the perpetual analog date at 6 o'clock frames the moon-phase display.

A new double-face case with a hobnail design

The Grandmaster Chime Ref. 6300 reveals at first sight that it is a new, distinctive creation. Its prominent white-gold case is decorated with a manually guilloched hobnail pattern seen only rarely in Patek Philippe's grand complication watches, even though this motif has been a trademark of the manufacture ever since the Ref. 96D was launched in 1934. The aesthetic exterior elements, from the mechanically elaborate case and the dials to the clasp reflect artisanal perfection and true engineering artistry. The reversing mechanism between the lugs is a technical masterpiece in its own right ; it guarantees that the watch can be worn with either dial facing up at any time.

The center of the black shimmering white-gold dial is decorated with a manually guilloched hobnail motif. The applied Breguet numerals in white gold, white printed scales, and white-gold hands assure optimized legibility. Although with opposite contrasts, this also applies to the opaline white dial of the perpetual calendar which groups four black subsidiary dials with black-oxidized steel hands around the centered four-digit year display in its discreet white-gold frame.

A user-friendly detail: The push pieces in the case flank are labeled with self-explanatory engravings. The function displays on the black dial (strikework mode, crown position, alarm mode, strikework isolator, power reserves of movement and strikework barrels) also provide clear and well-organized information concerning the individual functions and the selected modes of the watch. This proves that even a mechanical supercomplication can be a “smart watch” – an intelligent, easy-to-use timepiece.

Coordinated with the black/white duality of its dials, the Patek Philippe Grandmaster Chime Ref. 6300 in 18K white gold is worn on a shiny black alligator strap with large square scales and hand-stitched contrast seams secured by an 18K white-gold fold-over clasp.