Tank

The Tank is Cartier's rectangular wristwatch, but a rectangle alone does not explain its shape. Two long sides frame the dial and continue past it to hold the strap. Cartier calls these sides brancards. Case and strap form a continuous outline instead of a round watch with four small attachments.

Louis Cartier drew the Tank in 1917; it went on sale in 1919. The early design was compact and fairly square. Subsequent Tanks changed that outline so extensively that the name now describes a way of building a watch as much as one fixed shape.

The Tank Louis Cartier softened the long sides and corners. The Cintrée stretched the case and curved it. The Chinoise put conspicuous horizontal bars across its ends. Later, the Américaine developed the long, curved form further, while the Française made the bracelet a much larger part of the design. The familiar Roman numerals and blue hands often remained, but the proportions could produce very different watches.

There is no single Tank movement, either. Cartier has made hand-wound, automatic and quartz versions. A thin hand-wound mechanism allows a particularly shallow case, while quartz can keep the same basic arrangement with less attention from its owner. Neither tells you the shape by itself: the exact model and size matter.

The Collection Privée Cartier Paris Tank Louis belongs to a late-1990s return to historical forms and mechanical movements. Its small gold case, textured dial and two hands make a useful starting point for this family. There are fewer elements to distract from the decision that makes a Tank a Tank: how wide those two sides should be, how far they should extend, and how much face to leave between them.