Patek Philippe World Time Geneva Harbor 5131 (5131/175G-001)

It may not be the world's most complicated watch, but the new Grandmaster Chime by Patek Philippe is by far the most sophisticated striking watch in the history of wearable timepieces. Launched on the occasion of the brand's 175th anniversary, this monumental piece uses 1,366 components for the movement and 215 for the case in order to be able to strike out time like never before.

Let us start from the beginning: the Grandmaster Chime is a . This means that when the small indicator at 7 o'clock is in the G position, the watch will automatically chime the hours (one note for each hour) and the quarter hours (a three-note melody for each quarter). Proving that those who can do more can also do less, the calibre GS AL 36-750 QIS FUS IRM can also be switched to mode, in which case it will only chime the hours at the top of the hour and the quarter hours at each quarter. Finally, like any other minute repeater, the Grandmaster Chime will also chime the current time at the press of a button incorporated into the crown. 

As a reminder, the is the most sophisticated of horological complications. It is extremely rare and Patek Philippe did not have a wristwatch version in its catalogue. But on this already highly complicated base, Patek Philippe had added two additional functions, both of which are totally unique. 

Alarm and date
The first is an alarm. You may think that there is nothing unique in that. But this one doesn't sound the alarm with an indistinct bell. The Grandmaster Chime chimes the alarm time as if you had just pushed the minute-repeater button. It can be set to the nearest quarter of an hour. But to make sure it is heard, it always chimes more than just the hours. Thus, to wake up its owner at 7am, the watch will start chiming at 6.58. Instead of seven chimes it will chime six times for the hours, nine for the quarters and 13 for the remaining minutes.

But that's still not all. The Grandmaster Chime also chimes the date! It would appear that this is the first time ever that such a function has been implemented. The mechanism therefore has to be connected not only to a system that knows what time it is, but also to one that knows the date. Since the watch has a perpetual calendar, this system is already highly complex. But because of the imposing size of the movement, the date information must be obtained from the opposite end of the calibre. The striking mechanism has to chime the date, using the same principle as for the time. In order to avoid chiming up to 31 times, which would be bothersome to count for the wearer and would use up a lot of the movement's power, the Grandmaster Chime takes some shortcuts. First, it chimes a sequence of two notes in quick succession for the tens, then a single note for the remaining units. Those who want the watch to chime the month as well are quite frankly asking too much…

Two dials
The current time, alarm time and date can thus be consulted visually and audibly and are found on one of two dials on the Grandmaster Chime. The huge case, which measures 47mm in diameter by 16mm in height, is in fact reversible. It can be rotated around its lugs to reveal another face. The first is filled with indications and decoration, as well as two small and discreet windows. These are safety indicators that show whether the watch and alarm functions can be adjusted without any risk of damaging the movement. Patek Philippe has actually incorporated safety mechanisms into the incredible complexity of this movement to prevent the wearer from adjusting it inadvertently when the components are engaged.

The other dial is much purer. This second face is that of a complete perpetual calendar, showing day, date, month and a four-digit year at the centre of the dial in a large gold window. Just above this, to keep things practical, the time is indicated by two hands on a 24-hour scale. If required, it can be de-synchronised from the main time on the first dial in order to offer a second time zone display. We will pass over the perpetual calendar a little quickly, because it is a well-covered complication. Nevertheless, like all perpetual calendars by Patek Philippe, it is instantaneous: all the indications change simultaneously at midnight. This function becomes unique when the year changes, since in addition to five hands, at least one and at most three discs must be activated at the same time. For the fourth disc, which shows the thousand years, the force required to turn it has been calculated and will be available, but who will be around to check that it works? 

Four barrels
Listing the complications of the Grandmaster Chime, a total of 20, does not summarise its complexity. As with a number of other grand complications, it does not live off their accumulation but rather by their outcome. To this we must add the problem of power management of a difficulty never before seen in contemporary watchmaking. All the audible timekeeping from this piece comes from the This is what knows what time it is, not the hands, which are merely there to help us see the time. The components that really know the time have to distribute this information to three systems: alarm, calendar, striking mechanism, each of which require a power supply. This is why the Grandmaster Chime has four barrels. They guarantee a power reserve of 72 hours in silent mode and 30 hours in mode. This is much better than other models on the market and is no mean feat. They distribute their power to the different functions by means of a differential.

Only six models of the Grandmaster Chime will be available, at a price that would make an Emir perspire. A seventh model is reserved for the Patek Philippe museum. All of them have an ornate hand-engraved case in red gold, which is as complex as the movement. It has to house 11 pushers and buttons and guarantee the acoustic quality of the chimes, an element of quality for which Patek Philippe accepts no compromise. No easy task, given the numerous holes drilled into the case and the fact that it should be easily reversible. 

Seven years work

But the life of the calibre GS AL 36-750 QIS FUS IRM does not stop here. The brand has plans to use this colossal movement again in the future. This is just as well, given that it has taken seven years of work, 60,000 hours of development, production and implementation. It would have been sad to think that this masterpiece, which incorporates six patents, would not live beyond the celebration of this anniversary.