Replica A Lange Sohne Lange 1 Tourbillon Perpetual Calendar Platinum is a brilliant execution of the perpetual calendar; unlike the other Lange perpetuals all the displays here are arranged unconventionally but legibly and sensibly. The months are indicated on the perimeter of the dial by the arrow at six o’clock. Just above the arrow is the leap year indicator window.
The days are on the left, on a fan-shaped display. Above that is the trademark Lange framed date window. And there is also a moon phase display, as well as a small day and night at the bottom of the time sub-dial. 41.9 mm is well sized, not too large but big enough for all the calendar information to be easily readable. This watch has several notable features beyond what is obvious. It is an instantaneous perpetual, meaning all the calendar indications, including the oversized date, jump instantaneously at midnight.
The tourbillon is no ordinary tourbillon, instead it has Lange’s patented stop seconds mechanism which means the tourbillon cage is stopped when the crown is pulled to enable more accurate time setting. That being said the tourbillon is a superfluous (and overly expensive) feature in my opinion. The perpetual calendar is more than enough. And the tourbillon itself is not particularly attractive as the cage is mostly hidden.