A. Lange & Söhne Datograph Perpetual Tourbillon Lumen 740.055

Datograph Perpetual Tourbillon Lumen — 740.055

It's tough to write a caption about this watch. When I started writing Langepedia articles a while back, I was almost always focused on pluses and minuses, and the pieces were usually headlined “in-depth guide,” “collector's guide,” “understanding X,” and so on. The one for the Datograph Perpetual Tourbillon was titled something like “Admiring the DPT”, so you can tell how heavily biased I am when I say it might be one of the greatest watches ever made.

Take the unique pieces and emotional attachments out of the equation, and reference 740.055 is, without any doubt, the peak Datograph — and the peak Lumen.

It uses the Datograph Perpetual Tourbillon base for the dial. The indications sit within sub-dials rather than hanging free, forming a much more symmetrical, tidy, easy-to-read appearance akin to the base Datograph. The power reserve is removed for the visual integrity of the sapphire glass, so the tachymeter scale makes a full, uninterrupted run around the dial. The moonphase disc perfectly balances out the big date; it's now rendered with fantastic detailing and lumed generously. The day/night and leap-year indications are presented on discs, which add a lovely dash of color without disrupting any of the other indications.

The instantaneous perpetual calendar mechanism is visible beneath the dark sapphire glass. With the discs lumed, they pop from below in bright green. It's a menacing look. And yes, speaking of which, the calendar jumps exactly at midnight. Chatting with a great friend and collector who owns this piece, it struck me: this might be the peak of A. Lange & Söhne's design and technical accumulation over the last 30 years. It is here, and its name is Datograph Perpetual Tourbillon.

Caliber L952.4 is the near-impossible answer to the question of how you improve on the L951. It comprises 684 parts, carries a giant tourbillon beating at 2.5Hz, and is just as fantastically constructed and finished as its predecessor. The black-polished tourbillon bridge is flawlessly finished, and the large tourbillon carriage is shaped with three arms, a homage to pocket watches.

With its subtle honey gold case, enamel-esque sub-dials, brilliant arrangement of indications, the detailed moonphase, and of course its black sapphire dial, which has a way of capturing light like no other, the Datograph Perpetual Tourbillon Lumen reference 740.055 might just be the cherry on top of any Lange collection.

This watch comes with its original box and papers, and has now been sold to a great friend. Please have a read at Langepedia.com should you wish to learn more.