The 1815 RATTRAPANTE PERPETUAL CALENDAR unites two refined classic complications in a wristwatch: a rattrapante-chronograph and a perpetual calendar with a moon-phase display. When they designed these functions, Lange’s masters prioritised the use of traditional solutions that challenge the watchmaker’s abilities to the extremes.

In this movement with a total of 631 individual parts, the process of adjusting all switching sequences and thus of assuring optimised rate accuracy is a particularly challenging task. The perpetual calendar mechanism alone consists of 211 parts, and another 206 components constitute the rattrapante-chronograph mechanism. In the L101.1 manufacture calibre, high rate accuracy is guaranteed by a screw balance which is powered by a balance spring developed and crafted in-house.