The Lange 31 is an exercise in pushing what is possible, entirely designed around an astonishing 744-hour or 31-day power reserve. A record at release in 2007, it rather anachronistically does away with crown winding and brings back a ratcheting, torque-limiting key winding system—as the torque was far too high for thumbs alone to manage via a crown. It is a watch that pursues horology as sport, one which chose to push boundaries rather than meet client needs. The mass here is purposeful and fits entirely in early Lange's philosophy.
This was possible thanks to two large stacked mainsprings barrels, each 1850mm long, or nearly 4 meters in sum. That is an order of magnitude lengthier than a standard calibre. The torque these springs hold would rip apart a normal escapement, and so their power here is metered through a patented constant force remontoir. The manual calibre L034.1 requires 406 components and 62 jewels for this feat, with a 45.9mm case to house it. The L034.1 includes contrasting heat-blued and black polished screws, clear sapphire and red jewels, gold chatons, and a massive 3/4 plate with Glashütte stripes. It is a highly unusual calibre that exists purely for the sport of watchmaking. The dial simply states 'MONATS-WERK' (Monats is 'month' in German) with an oversized power reserve offset near 3. The dial's aperture, power reserve, and petite seconds are still arranged according to the golden ratio in the same way the Lange 1 is, just in a different configuration.
Here in platinum, the wearing experience is like nothing else, in mass and proportion. Lange as we know them today have never shied away from more solid cases, but deliberately so. In their reincarnation, Gunter Blümlein, then-CEO, believed a certain mass helped to give a sense of luxury. He is quoted in the early years as saying, 'When handling our watches, I want the owner to get the feeling of closing the door of a Mercedes.' That heft and solidity is nowhere more present than in the platinum Lange 31. Moreover, it bears the most elaborate deployant clasp Lange has ever made with twin triggers and a monumental locking system to counter the immense mass and ensure safe wearing. The platinum clasp was specifically engineered for this reference and is not found in any other Lange model. The Lange 31 was updated in 2015, but it is this ref. 130.025 which broke the record.
The Lange 31 has no successor in the modern range, though it influenced both the Zeitwerk and Terraluna heavily. Its size is inimitable, and a limiting factor for many; it's not for all. But the watch is not about proportions, it's about breaking records and watchmaking as a sport rather than bowing to client's needs; a first of its kind.