The A. Lange & Söhne trilogy celebrating 175 years of Saxon precision watchmaking also features a new interpretation of the 2017’s Tourbograph Perpetual ‘Pour le Mérite’ – a wristwatch that brings together five complications. The 175th anniversary edition is called the Tourbograph Perpetual Honeygold “Homage to F. A. Lange” and like the other two watches in the trilogy, this also features extensive use of Lange’s proprietary honey gold alloy.

The trio of honey gold case watches unveiled to mark the anniversary

When introduced in 1994, the A. Lange & Söhne Tourbillon Pour le Mérite was the first wristwatch with a tourbillon and a fusée-and-chain transmission. Since then, every ‘Pour le Mérite’ watch has used this archaic energy transmission system. In 2017 Lange unveiled the fifth watch with this special appellation, the Tourbograph Perpetual ‘Pour le Mérite’ – a horological heavyweight which combined a fusée-and-chain transmission, a tourbillon, a rattrapante chronograph, and a moon-phase perpetual calendar. Given the numerous complex mechanisms,  assembly of the 684-part manufacture caliber is entrusted to the Maison’s best watchmakers.

This year marks 175 years since the founding of Ferdinand A. Lange’s first pocketwatch workshop in Glashütte, an event that lead to the formation of the fine watchmaking industry in the eastern German town. Such is the town’s reputation now that master watchmaker and industry legend Philippe Dufour reckons Glashütte, not Switzerland, is the new reference for fine watchmaking. To mark the occasion, Lange unveiled a trio of watches including the sublime 1815 Thin Honeygold and the fabulous 1815 Honeygold Rattrapante chronograph.

The dial is made from black-rhodiumed honey gold

The new Tourbograph Perpetual uses a 43-mm-wide case that’s 16.6 mm-thick – an impressive feat considering the complexity of the movement that it houses. The watch has an impressive dial made of black-rhodiumed 18-carat honey gold. The dial has a real three-dimensional quality thanks to the relief-engraved numerals and scales, the numerals actually rise up 0.15 mm.  The perpetual calendar utilizes the three subsidiary dials to display the date, day of the week, month and leap year. The upper half of the analogue date also accommodates the moon-phase display, which is calculated to remain accurate for 122.6 years. The moon-phase disc is also made of honey gold, so are the hands of the time and calendar displays.

The numerals and tracks are relief engraved on the dial

One of the biggest challenges for the watchmakers was keeping the thickness of the watch within reason. Just adding a perpetual calendar module to the 2005 model’s base caliber wouldn’t cut it. So the team had to redesign the movement with the perpetual calendar mechanism arranged under the dial around the tourbillon. The addition of an extra layer has also resulted in the use of a curved tourbillon bridge that has a black-polished finish.

The bridges have a granular finish and black-rhodiumed engraving

Flip the watch over to view the manufacture caliber L133.1 made up of 684 parts. Like the other watches in the 175th anniversary trilogy, the movement’s German silver bridges have a granular finish and black rhodiumed engravings, the granular texture of the bridge is a nod to the kind of finishing seen on the pocketwatches made by F. A. Lange. The tourbillon cage is suspended between two diamond endstones as was the case in those historic pocketwatches of the then highest quality level, the 1A category. Other technical details of that category included a balance wheel with gold poising screws and screwed gold chatons to secure the bearing jewels. To top it off, a diamond endstone is integrated in the hand-engraved balance cock.

The finished is exemplary, with a mix of polished and brushed surfaces and chamfered edges, thermally blued screws, and screwed gold chatons; the chronograph bridge is also engraved by hand. The watch has a power reserve of 36 hours and a balance that oscillates at 3 Hz (21,600 vph) and is paired with a dark brown leather strap. Limited to just 50 pieces, this watch is priced at €500,000.