Patek Philippe Ref. 5159 Perpetual Calendar

Grand Complication. There is a difference of opinion among horologist as to what constitutes a Grand Complication. Some define a grand complication as one having at least one complication from the three different groups: Timing, astronomical and striking complications. Other horologist claim that there are three grand complications, the Tourbillon, the Minute Repeater and the Perpetual Calendar.

Perpetual Calendar. Many watches display the date on their dial. But since some months have only thirty, twenty-nine of twenty-eight days, you need to adjust the date at least five time per year. A perpetual calendar is a mechanism that automatically takes into account the varying number of days in each month as well as leap years so that the watch displays the correct date each month without the need of adjustment. A perpetual calendar watch will not need correction for more then a century.

Patek Philippe has played a key role in the development of the perpetual calendar mechanism. In 1889, Patek Philippe obtained a patent for the "Perpetual calendar mechanism" for pocket watches. In 1925, Patek Philippe created the first perpetual calendar wristwatch. Patek Philippe began regular production of Perpetual calendar wristwatches in 1941. Development continued, a more recently, Patents for Secular Perpetual calendar with retrograde hand for the Annual calendar mechanism were obtained by Patek Philippe in 1986 and 1996.

Patek Philippe Ref. 5159. The Patek Philippe Ref. 5159 is one of the company's grand complication watches. It is a perpetual calendar watch with the retrograde complication.


The Patek Philippe Ref. 5159 is a revision of the Ref. 5059, with the case diameter being enlarged by 2 mm, to a size of 38 millimeters. Powering the Ref. 5159 is Patek's caliber 315 S QR movement. S stands for sweep seconds, Q for perpetual calendar, and R for the retrograde date with the flyback hand.

The self winding movement produces 28,800 vibrations per hour, resulting in a smooth sweeping seconds hand. The movement has a 44 hour power reserve. The movement automatically recognizes the duration of each month and keeps track of leap years.

The dial of the watch displays the day and month in apertures at the 9 and 3 o'clock positions. The date is displayed by a red-tipped fourth hand, which runs from the 8 o'clock to the 4 o'clock position. This hand moves clockwise from the 8 o'clock to the 4 o'clock position, along a 270 degree arc, slowly over the period of one month, and than jumps back to the number 1 at the end of the month moving in the reverse direction. This is the retrograde motion.


The month setting, tells the watch whether it should send the hand back to 1 after the 28th, 30th or 31st day. A small aperture just below the 12 o'clock displays the Roman numerals I, II, III or IV. This is the leap year indicator. When it displays a I, II or III, the watch will send the date hand back to one after the 28th day of the month of February. When it reads IV, the watch will send the date hand back to one after the 29th day of the month of February.

The month setting and the leap year setting allows the watch to adjust the movement of the date hand accordingly, this creating a perpetual calendar mechanism.

The Ref. 5159 also has of the moon-phase mechanism which remains accurate for 122 years and 45 days, and then only has to be corrected by one day.

To execute these complicated functions, 361 individual parts must interact in perfect harmony. A sapphire-crystal case back reveals the intricate self-winding mechanism and the 21K gold rotor. A dust cover protects the sapphire crystal case back.


The Ref. 5159 is available in 18K yellow (Ref. 5159J) or white gold (Ref. 5159G) . It ts worn on an alligator strap with an 18K foldover clasp. The yellow-gold watch has a matte chocolate strap and the white-gold model comes with a matte dark brown strap.

With a retail price of just over US$80,000, it is neither the most expensive nor he most complicated watch Patek Philippe has created. It is still an amazing piece of watchmaking, and in my opinion one of the best example of complication watchmaking in the Patek Philippe lineup. It is impressively complicated, without cramming in so many complications as to make it appear that the watch was created solely for the purpose of making it complicated. Every complication in this watch all leads to the same end, a perpetual calendar displayed in Arabic and astronomical terms.

About Patek Philippe. Patek Philippe & Co. was founded in Switzerland in 1851. The companies emblem, the Calatrava Cross, was adopted by it at the end of the 19th Century. It is acknowledged as one of the finest, if not the finest, watchmaker in the world.