1940s Cartier Tank Allongée 'Duoplan' Two-Tone 18K YG & WG Case W/ 18K RG Bracelet

The Cartier name is synonymous with luxury and has been since the brand's inception in 1847. Offering bespoke and unique jewelry to the world’s elite allowed Cartier to grow steadily through the 19th century and eventually introduced new offerings to their clientele. While the most recognizable watch models such as the Tank, Baignoire, and Santos Dumont are primarily celebrated and deseringly so, throughout Cartier's illustrious heritage the Maison created and produced numerous watch designs, from the most simple to extravagant.

Being that Cartier was always a design and jewelry house first, they never really entered the realm of high-watchmaking themselves. Instead, the Maison was a resourceful collaborator with master watchmakers to supply the movement for their designs to encase, most notably Audemars Piguet and Jaeger-LeCoultre, as well as the European Watch & Clock Company which was a joint venture between Edmund Jaeger and Cartier. It's believed that one of the most innovative movements was developed through this collaboration, the Duo-Plan, changing the possibilities of watchmaking forever.

Allegedly, Jaeger-LeCoultre developed the Duo-Plan movement for Cartier exclusively at first. This unique system was created to make the smallest possible watch movements, and this was accomplished by stacking the movement components on two planes, hence the name "Duo-Plan". This effectively reduced the footprint of the movement by half without compromising the integrity or quality of the components. The Duo-Plan movement family consisted of 4 calibers, with the cal. 101 being the smallest and still sparingly produced today, followed by the cal. 104, cal. 403, and the cal. 409 all slightly increasing in size respectively. It's believed that Cartier's exclusivity of the Duo-Plan ended in 1922, opening up JLC and other brands to create their own designs using the Duo-Plan system. That didn't stop Cartier from utilizing the Duo-Plan movement, however, with some incredibly unique watches being created by Cartier using the system throughout the 20th century. 

This extravagant, unique, and beautiful Cartier Tank Allongée from the 1940s employs the iconic cal. 409 Duo-Plan movement, which accomplishes a very symmetrical aesthetic with the backwind design. More interestingly, however, is the construction of the case itself, consisting of a seamless 18K yellow gold and 18K white gold two-tone construction. Completing this tri-metal design is the 18K rose gold bracelet, which perfectly complements the bright salmon-colored dial.