Slate is the cool ground on a warm watch, and on this configuration it is the only element that does not belong to the Everose family. Reference 278381RBR is the 31mm Datejust in a combination of stainless steel and Everose gold, carrying a rim set with diamonds, and this configuration pairs a slate dial with eleven plain gold Roman numerals, an oversized six set with diamonds, and an Oyster bracelet. The color choice changes what the setting does. On chocolate or rose the stones sit within a warm scheme and read as part of it; on a mid-grey ground they sit against something neutral, and both the plain numerals and the set six separate more sharply than they do on any warm dial this reference builds.
Slate is the middle value of the neutrals, darker than silver and lighter than black, and its useful property is that it moves. Under flat daylight it reads as a clean grey; under a warm lamp it takes some of the surrounding light and drifts toward brown, and in an Everose case with a set rim there is a good deal of warm light being thrown at it. So the dial is neutral by specification and variable in practice, and the amount of warmth it picks up depends on where the watch is being worn. The eleven plain numerals are solid gold matched to the case, and against a mid-value ground they hold steady contrast in a way they cannot manage on chocolate, where depth alone separates them. The enlarged six is the exception to everything else on the dial: bigger than its neighbors, set with stones, and positioned directly opposite the twelve, which gives a small face a definite bottom. The rim above carries its own ring of stones. The Oyster bracelet holds steel in broad flat sections, keeping the cool half of the watch permanently in view and giving the slate dial something at the wrist that agrees with it. The two cool areas are not the same cool, which is part of why the combination works. Brushed steel is a bright neutral that holds one value.
The function set stays short. Hours, minutes, running seconds and a date that changes instantly at midnight rather than drifting into place across the small hours. That instantaneous change is the feature the model introduced and the reason it stands as its own line, and it remains the difference between a date designed into a watch and one added to a movement finished without it. The self-winding movement in the 31mm case holds roughly fifty-five hours of running time, matching the 28mm watches rather than the larger references, since the small cases use a different movement. Nothing else has been added, and on a dial carrying twelve numerals of unequal size there is no room for anything further without disturbing the arrangement. Slate is one of three grounds on this reference carrying the enlarged six, alongside aubergine and chocolate, and the only one of the three also offered plain. That gives a buyer a direct comparison the other two do not: the same ground with and without the treatment, on the same case and the same bezel. The enlarged six itself belongs to this diameter and appears at no other diameter in the range, which makes the comparison available only here.
The oversized six is exclusive to this diameter. Sixteen references carry it and all sixteen are 31mm, which puts it alongside the stone-set nine at 28mm and the set six and nine at 36mm as one of three separate single-numeral languages, each confined to its own case size. Unlike the 28mm version it is not restricted by metal, appearing across solid Everose, yellow and white gold and all three two-tone constructions, and it is offered on seven grounds including this one. Slate itself is widely built, on thirty-two references from 31mm to 42mm, and it is absent only from the 28mm cases, so this is the smallest watch on which the ground can be had at all. Within the reference the natural comparison is the chocolate version of the same treatment, which keeps everything inside one warm family, where this configuration sets a cool dial against a warm case and lets the two hold apart. The wider range makes the same point across sizes. Slate is offered on thirty-two references and almost all of them are steel or two-tone rather than solid gold, so a grey dial is normally found on a watch with steel in it. Putting it on a case with a set rim, as this reference does, is the less common arrangement and it produces a watch that is formal and sober at the same time, which most set dials are not. It is also the reason this configuration turns up on more wrists during the working week than the warm versions of the same watch do. A chocolate or rose dial under a set rim announces itself as a piece of jewelry from the first glance, where a grey dial makes the same components read as a watch that happens to be well made, and the difference is entirely in the ground since everything else on the two pieces is identical.
This suits a buyer who wants a set watch that stays sober. Slate keeps the dial businesslike while the rim and the six supply the brightness, and the Oyster keeps steel in view so the piece never reads as a gold watch with a grey face. It is the most restrained combination this reference offers among the dials carrying an enlarged numeral, and it works across a working day in a way the warmer configurations do not quite manage. Anyone who wants the watch to read warmer should take the Jubilee version, where the bracelet blurs into gold. Anyone who wants the dial to belong to the case rather than stand against it should take chocolate or rose, both of which settle into the same register as the metal. This is the version bought by people who want the watch to be correct in an office and unremarkable on the way home, and there are not many set dials that manage both.
