Rehaut

The rehaut is the vertical or angled band that separates the dial from the inner edge of the case, beneath the crystal. It is neither the bezel nor the dial: it is the cylindrical space between the two. Often overlooked, but from the workbench you immediately understand how much work has gone into it.

Its primary function is structural: the rehaut acts as a seat for the crystal and visually seals the transition between the glass and the dial. On dive watches, like the Citizen Promaster Mechanical Diver, this band is pronounced and creates real optical depth between the crystal and the dial plane. On the VPC Type 37HW, the rehaut was reduced to a minimum to lower the total case height to 9.8 mm without sacrificing 120 metres of water resistance: a precise design choice, not an aesthetic detail.

When the surface is angled toward the dial, as on the Certina DS-X GMT or the Unimatic Modello Cinque, the effect is to visually enlarge the dial: the perceived diameter increases without touching the actual case dimensions. It is one of watchmaking's honest tricks.

Functional scales are often found on the rehaut. Yema watches from the Seventies used it systematically: the Rallygraf displayed the elapsed time scale, the Flygraf fuel conversion charts. The Nodus Obscura II prints ISO values and aperture numbers there. The Doxa Sub 250T GMT features a 24-hour GMT scale in two colours, day and night. The Breitling Superocean places the minutes scale in anthracite. All examples where the rehaut works, rather than decorates.

Rolex introduced laser-engraved repeating brand names on the rehaut of nearly all its models around 2004. The alignment precision required makes this one of the most difficult solutions to replicate for counterfeiters: I still see this when pieces are brought to me for verification.

The finish can be satin, diamond-pointed guilloché like on the Polerouter SAS, or polished mirror. The TAG Heuer Carrera Glassbox even has a curved rehaut that follows the dome of the sapphire crystal, emphasising the three-dimensionality of the entire dial. Not every manufacturer chooses to enhance this area, but when they do with purpose, the result substantially changes how you perceive the watch.