A perpetual calendar is like a small computer on your wrist.

Think of it this way: Imagine a watch that keeps track of not only the time, but also the date, the day of the week, and the month, and also tells you whether it’s a leap year or not, and what the current phase of the moon is. Oh, and one more thing — imagine it does all of this mechanically, using springs and gears, and that you only have to adjust it once every century or so. Crazy, right?

Leave it to Patek Philippe to take this mechanical concept a step further.

In 2012, the maison introduced the Reference 5204. Handsomely equipped with a perpetual calendar complication, Patek Philippe flexed their mechanical prowess by adding a split seconds chronograph into the mix. 

What we have here, is a Reference 5204R-001, a more contemporary model that debuted in 2016. Housed in a 40mm 18K rose gold case, this piece features a pair of rose gold barrel chronograph pushers and a knurled crown with an integrated pusher responsible for managing the split seconds functionality. The number of small details including finishing and mindful design cues amount to what feels like a special object worthy of high-level complication.

The dial is yet another masterpiece in symmetry with all of its information and displays balanced beautifully throughout. Featuring applied, luminous rose gold applique indices and a matching dauphine handset, this piece is further complemented by a triple register display, moonphase, day/night indicator and a leap year aperture. 

This piece is powered by the manual-winding Calibre 29-535 column wheel movement built with a lateral clutch and handmade Breguet overcoil. What this translates to is a movement that only the most experienced Patek Philippe watchmakers are able to, and allowed, to work on at the manufacture.

It's absolutely a piece of horological art — a true heirloom piece that gets passed down through the generations.