Patek Philippe Perpetual Calendar Chronograph 3970 (3970R_Breguet.)

Launched in 2006, the Patek Philippe Annual Calendar Chronograph in platinum was the manufacture's first self-winding chronograph. It manifested a new and unique style with its prominent monocounter and three large calendar apertures, and quickly established itself as one of the most coveted timepieces of the Patek Philippe portfolio. Now, the letter "A" in the model designation 5960/1A, which stands for acier (steel in French), announces a paradigm change. The Annual Calendar Chronograph in stainless steel is not only the latest sibling of its lineage but will also replace all current gold and platinum versions.

Patek Philippe's stainless steel watches have always ranked among the most desirable timepieces because they were crafted only in small numbers. They were not regularly produced until 1976, when the manufacture introduced the casually elegant Nautilus line. Its memorable slogan: "One of the world's most expensive watches is made of steel." Twenty years later, the Aquanaut was also endowed with a stainless steel case. With very few exceptions - such as the ultra-thin Ref. 5950A split-seconds chronograph which has been in the collection since 2010 - all other Patek Philippe men's wristwatches were systematically cased in gold or platinum. As regards this strict distinction between casual and classic watches, the new Ref. 5960/1A is another one of these seductive exceptions.

The new stainless steel case imbues the Annual Calendar Chronograph with authoritative technical finesse. It emphasizes the active and dynamic nature of the chronograph and underscores its function as a convenient timekeeping instrument of everyday utility. Nonetheless, the new Ref. 5960/1A has a decidedly elegant nimbus attributable to the balanced, gently rounded case contours and the superb finishing touches that reflect the competence of Patek Philippe's casemaking ateliers. The artisans are required to accrue several years of experience before being entrusted with the finissage of the manufacture's cases. Because of its hardness, stainless steel challenges the skills of the case specialists and imposes special requirements on their tools. 

The elegance of the case is highlighted by the signature bracelet with its five rows of "drop" links. It is eminently supple and of filigreed elegance. Developed by Patek Philippe, this bracelet was first introduced in 1997 for the Ref. 5036/1 Annual Calendar and now celebrates its debut in stainless steel.
 

Technical elegance also characterizes the new silvery-gray dial with its striking red accents, interesting bright-dark contrasts, and the dynamic, performance-oriented looks of its explicitly three-dimensional architecture. A red "1" in the date aperture kicks off each month with a colorful stimulus while the dates from the 2nd to the 31st days are displayed black on white. Thirteen appliques in black oxidized gold produce the expressive 3D effect: the chronograph scale on the periphery of the dial with twelve luminous five-minute markers, the three distinctively contoured frames for the aperture displays of the day, date, and month, the eight pointed-baton hour markers, each with three facets and a recessed sink at the flat end, as well as the 12-hour counter scale at 6 o'clock. 
 

Additionally, the dial features two printed concentric chronograph minute counter scales (0 to 30 and 30 to 60 minutes) within the applied hour counter scale, a small day/night indication at 6 o'clock, and the minus and plus symbols for the power-reserve indicator beneath the date aperture. The redesigned hands of the Ref. 5960/1A accentuate the dynamic elegance of the watch. The hour and minute hands in black oxidized gold feature three facets to match the hour markers and have a luminescent coating. The brass hour-counter hand is black nickel-plated to match the applied counter scale. The large counterbalanced chronograph hand in steel and the small minute-counter hand in brass are bright red as dynamic hints that they are used for measurements in competitive sports. The power-reserve hand in black nickel-plated gold was redesigned as well. It is now wider and skeletonized.

The hands and the calendar displays are powered by the Patek Philippe CH 28-520 IRM QA 24H caliber with flyback chronograph and Annual Calendar as well as power-reserve and day/night indications. It beats with a frequency of 28,800 semi-oscillations per hour (4 hertz), which assures a constant balance amplitude and thus high rate accuracy. A heavy central rotor in 21K gold winds the watch automatically.

The movement is a prime example of tradition paired with innovation. It combines the classic column-wheel control concept with a modern vertical disk clutch that eliminates the risk of hand jump or recoil when the stopwatch function is activated. The clutch is practically friction-free, so that the chronograph hand can be used as a permanently running seconds hand if desired.

The patented Spiromax® balance spring made of Silinvar® is another innovative feature. Its isochronous oscillation, low mass, antimagnetic properties, and unique geometry assure high rate stability and uniformity. These are ideal prerequisites for the fulfillment of the Patek Philippe Seal precision criteria which for mechanical movements of this size tolerate a rate deviation of no more than -3 to +2 seconds per day.

This rate accuracy also benefits the patented Patek Philippe Annual Calendar, a modular ensemble that is a scant 2.48 mm high despite its 154 parts. Displaying the first day of the month in red, the calendar automatically recognizes months with 30 and 31 days and only needs to be manually corrected by one day on March 1 of each year.

As of this year, Patek Philippe's new Annual Calendar Chronograph 5960/1A replaces all Ref. 5960 Annual Calendar Chronographs in gold and platinum.