To pay tribute to its 175th anniversary, Patek Philippe created a collection of limited-edition commemorative timepieces, and one of them stands out in particular. It is the so far most complicated wristwatch of the eminent family-owned watchmaking company and decidedly one of the world's most elaborate wristwatches. This is due not only to the number of complications involved but also to the horological degrees of complexity, two of which have been added to the annals of watchmaking for the first time. Moreover, the Grandmaster Chime is the first double-face wristwatch presented by Patek Philippe that can be worn with either dial facing up: the one that focuses on the time and the sonnerie, the other dedicated to the full instantaneous perpetual calendar. Changing the face is very simple thanks to the ingenious reversing mechanism in the lugs. It is amazingly easy to operate and firmly secures the case in the selected position. Incidentally, the information for which a watch is most frequently consulted – the current time and the date – is displayed on both dials. The ultimate in user-friendliness and safety is assured with intelligent mechanisms that prevent potentially damaging manipulations and thus reliably protect the highly complex movement with its intricate cosmos of tiny parts.