In 1991, the soon-to-be graduates at the Geneva School of Engineering were presented with their final project prior to receiving their diploma: to simplify the perpetual calendar.

Although the task was easier said than done, their work led to the inception of the annual calendar complication, patented by Patek in collaboration with the bright engineering minds at the GSE. Five years later, Patek debuted the Reference 5035, the worlds first-ever annual calendar movement that finally bridged the gap between a triple date function and the formidable quantime perptuel . (An annual calendar requires adjusting once per year at the end of February, while the perpetual calendar requires no adjustment for many years.)

This piece, a handsome modern interpretation of the Patek Philippe Complications Annual Calendar, transports us forward to the 2010s. A Reference 5396/1R-001, this lovely timepiece features a 38.5mm 18K rose gold case with sculpted, contoured lugs, a concave bezel, a signed crown, a sapphire crystal, and polished finishing.

The incredible brown sunray dial is a picture of economy, with applied rose gold indices, a matching dauphine handset, and displays for the day, date, and month punctuated by a beautiful moon phase/24-hour display above 6 oclock that also doubles as the watchs running seconds indicator.

The reverse side of the case features an exhibition back providing a window to admire the self-winding Caliber 324 S QA LU, whose mesmerizing 21K gold winding rotor is adorned with the hallmark Patek Philippe seal. Fitted to an exquisite rose gold multi-link bracelet with a signed clasp, this piece is accompanied by its factory goodies dating to circa 2012.

Theres no doubt the Nautilus and Aquanaut have gotten their time in the sun, and even vintage Patek Philippe continues to demand the attention of any savvy collector. But let us not forget the high-complication heavy-hitters such as this, hiding in plain sight in Pateks modern catalog!