What do most sons buy their fathers for a milestone birthday? Maybe a nice bottle of wine from their birth year. Or a pair of monogrammed cufflinks. Or, if it’s a really significant one, perhaps even a watch.

Well, if you’re Thierry Stern and your father is turning 85, the answer is not just to give him a watch, but build 30 of them from scratch, armed with a movement so rare and refined it will never be used again. Next step, engrave his signature on the balance weight and paint his portrait on its dial. And the final touch? A hinged dust cover hand-engraved: “À mon père, 85 ans de passion horlogère”.

The Patek Philippe Minute Repeater Alarm Ref 1938P-001 is a masterclass in fine watchmaking. It’s not just a ticking tribute to Philippe Stern – this is one for pure Patekoholics. The kind of people that dream of Gyromax balance wheels, wake up thinking of silicon escapements, and check their perpetual calendar before their Google calendar.

Patek Philippe Minute Repeater Alarm Ref 1938P-001
Patek Philippe Minute Repeater Alarm Ref 1938P-001

The brand-new movement inside the Ref 1938P-001 has been developed exclusively for this timepiece. The new self-winding R AL 27 PS calibre combines a minute repeater – Stern Snr’s favourite complication – with an alarm chiming the programmed time on the same two classic gongs. The combination of these two functions is harder than it sounds (literally): it requires the addition of 227 components and resulted in Patek filing four new patents.

The finishing of this exclusive movement is particularly intricate, as the edges of the bridges and hammers are gilded. A similar effect is carried through to the mini-rotor: rhodium-plated with yellow gold edges, framing the black lacquered hand-engraving of Philippe Stern’s signature.

On the face, you’ll find a Grand Feu black enamel dial, with a miniature painting of Philippe Stern in Grand Feu white and grey. It’s somewhat evocative of the iconic black-and-white portrait of Francis Ford-Coppola's 1972 film The Godfather – a fitting comparison given Philippe’s position at the head of the family.

It’s not just Mr Stern’s 85th birthday this year – but 30 years since he was made president of the maison. Although his title is now honorary, his presence at Patek Philippe’s core will no doubt be perpetual.

For more information, see patek.com