The Grande Complication No. 42500 is a high-quality, historical pocket watch and a Unique from A. Lange & Söhne .

The Grand Complication No. 42500 pocket watch was built in 1902 by A. Lange & Söhne, Glashütte. ^{[ 1 ]} She is one of the most complicated pocket watches ever made worldwide. It has a self-strike mechanism Percussion with hourly large and quarter-hourly small bells, a minute repeater , a Split - second chronographs , stopwatch with intermediate time and fifth-second division.

In addition to the main dial, the watch has 4 small circular displays, which are a Perpetual calendar on the 12, a daily newspaper in the current month on the 3, a Moon phases display at 6 and a weekday display at 9.

The calendar synchronizes all displays except the moon daily at exactly midnight. clockwork with nickel-plated Worktop out of nickel silver consists of 833 individual parts. The watch weighs just under 300 grams. All Arabic numerals and the symbols on the Enamel plate are hand-painted.

The design of the engraving of the gold case comes from Carl Ludwig Theodor Graff , Director of the Royal Saxon School of Arts and Crafts in Dresden. It was designed and awarded in 1890 for a competition, Johannes Dürrstein had advertised.

The craftsmanship comes from engraver Gustav Gessner , Glashütte ^{[ 2 ]} , for the 42500. On the front side, the case shows the head of the goddess Minerva as a symbol of the belief in progress at the time. The back of the watch bears the monogram "GS" in the center.

On both sides, two birds facing each other, two cornucopias and garlands can be seen. ^{[ 3 ]} The watch's frame, as well as the crown and its bow, are decorated with multi-row, repeating, miniaturized engraved ornaments. The movement is housed in a 750/1000 rose gold case. in the form Louis XV with factory glazing.

The watch of the type Grand Complication as a pocket watch was only produced by A. Lange & Söhne as a Unique manufactured, as was typical for watch manufacturers at the time for such high-quality watches. A Grande Complication was the "flagship" of a manufacturer. ^{[ 5 ]}

The center for complication watches with a high level of vertical integration had developed in western Switzerland at the end of the 19th century. The Glashütte Union Watch Factory purchased three ebauches from there for the planned construction of highly complicated pocket watches. They were scheduled for production in 1895 to mark the 50th anniversary of watchmaking in Glashütte and offered for sale as a "universal watch." The 42500 is based on such an ebauch.

Built in 1902, Grand Complication bears the serial number 42500 and was sold to a Viennese private individual in Glashütte in August 1902. The purchase price was verifiably a handwritten entry in the A. Lange & Söhne company's register from the German Watch Museum Glashütte 5,600 Goldmark .

It returned to the manufacturer in 2001 in a completely rusted, incomplete, and partially destroyed state. The movement was most severely damaged; ^the calendar and bridge were in a more easily restored condition. At the August floods 2002 in the Ore Mountains, which affected the company building, the clock was not affected by a coincidence.

However, the flooding and legal issues with the owner delayed the start of the restoration of the 42500. A. Lange & Söhne ultimately undertook a complete restoration of the watch from 2003 to 2006 under the direction of Jan Sliva and a team of five specialists. The effort amounted to 5,000 hours of work.

In contrast to usual restorations, where the preservation of the original parts is given priority over the functionality of the system, three objectives were set for the restoration of this example in this order: Firstly, the clock should be as perfect as possible look compared to the time of their production.

Secondly, it should be as perfect as in 1902 function and thirdly, as many original parts as possible be used. ^{[ 9 ]} To achieve these goals, not only did new, non-repairable parts have to be manufactured, but tools, molds, and processes also had to be developed. All screws were replaced.

The watch was exhibited for the first time at the Geneva Watch Salon (Salon International de la Haute Horlogerie) in 2010. The watch is now on permanent loan to the Mathematical-Physical Salon of the kennel in Dresden .

The existence and whereabouts of this watch were repeatedly debated in expert circles before its reappearance. Its precise identification, the unique stopwatch mechanism with a fifth-of-a-second accuracy, the reset mechanism for all functions, and the painstaking restoration by the manufacturer themselves give it a cultural-historical value with an incomparably high and incalculably high hypothetical auction value.

The fact that its history is not fully known and that new parts were used in the restoration does not diminish its value in auction circles. The number of specialists qualified to restore this watch to the quality achieved was estimated at fewer than 20 worldwide.