Hailing from an extended family of perpetual calendar chronographs, the Patek Philippe Perpetual Calendar Chronograph ref. 5971 is a timepiece that embodies the famed watchmakers traditional approach to both Haute Joaillerie and Haute Horlogerie. Launched in 2007 and produced for a short three years until 2010 (the shortest of any perpetual calendar chronograph model), the ref. 5971 was offered as a diamond-set version of its functionally identical sibling, the ref. 5970. The last Patek perpetual calendar chronograph reference to feature a Lemania caliber, the ref. 5971, like its plainer sibling, marked the end of a defining era within Pateks long and storied past. Powered by one of the most stunning column wheel chronograph movements ever made, the ref. 5791 displays behind its exhibition caseback the beautiful Lemania cal. CH 27-70Q movement. Produced exclusively for Patek Philippe, this labyrinthine movement combines a perpetual calendar within its chronograph subdials in keeping with the iconic design language of its predecessor, the ref. 1518. Featuring a leap-year indicator, a pointer date, a 24-hour indicator, and a moon phase all within its three subdials and the day and month within two apertures at 12 oclock, the ref. 5971s matte black dial is as well-balanced and symmetrical as possible. With its beautiful diamond-set hour markers, the ref. 5971 gently hints at what makes it so special, its case. Found within a modern 40mm platinum case, the ref. 5971 features 36 Top Wesselton baguette-cut diamonds set across its bezel, weighing approximately 4 carats. Featuring a polished finish across the entirety of its case except for its square pushers (another homage to the ref. 1518), the ref. 5971 is a mass of sparkling platinum and diamonds, resulting in a fantastically luxurious aesthetic, an aesthetic supported by the ref. 5971s historic design and rich history within Pateks catalog. Offered here, our 2009 example was one of the last few pieces produced by Patek and is found in fantastic condition with what is likely to be its original finish. Furthermore, it has its original box, papers, and solid caseback, should its owner decide to add even more heft to their wrist.