The leaf hand is one of the oldest forms in the classical watchmaking repertoire: wide at the base, it tapers progressively toward the tip following a continuous curve that recalls the profile of a leaf. It's not an applied decoration—the geometry itself determines legibility. The maximum width, positioned in the lower third of the hand, falls exactly where the dial has the most free space between center and indices; the tapering brings the tip close to the indices without overlapping. It's a functional balance before an aesthetic one.
Over my years at the bench, I've handled leaf hands from very different eras, and the difference lies in the cross-section. The best ones are flat and nearly sharp-edged, with a crisp edge that catches light distinctly: just a few degrees of wrist rotation are enough to shift from white to black. More recent, less carefully made versions tend to be generically convex, losing that interplay of reflection that is the true strength of the form. Some manufacturers curve the hand slightly along the longitudinal axis to follow the domed profile of the crystal: a detail you won't see in catalogs, but in person it makes a difference in the perception of depth.
The color is traditionally blued steel, obtained through controlled thermal oxidation. The resulting blue is not uniform: it varies from cobalt to indigo depending on the metal's thickness and temperature reached, and this is the sign that the process was done by hand. Rhodiumed or gilded leaf hands belong more to the contemporary dress segment; burnished or black PVD versions appear on some sports watches, but the form loses its purpose in that context because legibility gains nothing compared to a baton or sword hand.
In Anglo-Saxon terminology you almost always find it as leaf hand or leaf-shaped hand. In French, one speaks of aiguille feuille. The association with Art Deco style is correct but partial: the form already existed in the nineteenth century on pocket watches, and it survived design trends because it solves a real problem. Confusing it with the dauphine is a common mistake: the dauphine has a double-ramp section that creates a much more pronounced V effect, while the leaf maintains a flatter, more extended silhouette.