With nothing set into the dial, the bezel is the entire ornament on this watch. Reference 278343RBR is the 31mm Datejust in a combination of stainless steel and yellow gold with a domed bezel set with diamonds, and this configuration pairs it with a plain white dial and applied Roman numerals, on the Oyster bracelet. The dial carries no stones, the bracelet carries none, and the case is otherwise the same shape Rolex has built for decades, so every decorative decision on the object has been concentrated into a single ring around the crystal. White is the one ground at this reference that never carries stones, which puts the whole of the decoration on the bezel.
That concentration works differently on yellow gold than it does on white. Setting stones into a white gold bezel largely conceals the metal, since the two read at similar brightness and the diamonds take over the surface, and yellow gold is visible enough that the stones read as an addition to it rather than a replacement for it. The bezel here is unmistakably gold with diamonds in it, which is the older and more emphatic way of presenting a set watch, and it is why a yellow two-tone reference with a set bezel reads as considerably more decorated than a white one carrying the same stones. The stones are seated individually into recesses cut in the gold rather than dropped into a preformed channel, and on a ring this small there is less circumference to absorb an error, so the tolerances run tighter than they would on a larger bezel. Steel and yellow gold is the most visible two-metal pairing Rolex makes, since yellow gold sits nowhere near steel in color and every junction between them reads as a clear boundary between materials. The steel forms the case and the outer bracelet links while the gold takes the bezel, the crown, the bracelet center rows and the numerals, and the gold is solid rather than plated or capped. The dial is plain white lacquer finished flat rather than with a sunray, the harder choice since a brushed surface would conceal the small variations a flat white reveals. The Roman numerals are applied yellow gold and faceted, drawn for this case size rather than scaled from a larger one, and against white they read as unambiguously warm shapes. The bracelet is the Oyster, three broad flat links brushed across the top with polished flanks. The date at three displaces the numeral that would otherwise sit there. The hands are polished yellow gold and drawn short of the numerals so they cross the dial without appearing to touch them.
Against white lacquer the magnified date is about as legible as a date window gets, and a single aperture is what allows a full Roman sequence to fit at all. The Cyclops lens above it has been part of the Datejust since 1953 and magnifies the date roughly two and a half times, which makes a small window readable without enlarging it and unbalancing the dial. The date changes instantaneously at midnight rather than creeping through the surrounding hour, the feature the Datejust introduced in 1945 and the one it takes its name from. Correction runs through the winding crown without moving the hands, and nothing the watch asks for requires a tool. The movement is self-winding with a power reserve of approximately 55 hours, an engineering result on a movement built to fit a 31mm case rather than a figure carried down the range, since a smaller barrel has less room to store energy and a proportionally smaller rotor gathers less of it. The rotor winds in both directions rather than only one. The crown screws down against the case, and the Oyster closes with a concealed clasp folded away inside the links. Hand winding runs through the same crown with no separate position to learn.
The Datejust arrived in 1945 as the first self-winding wristwatch to show the date in a window, and the 31mm case sits between the 28mm Lady-Datejust and the 36mm original, which makes it the size for buyers who find one too small and the other too large. The 278000 generation replaced the 178000 series in 2018 with a revised case and bracelet. Rolex registered the name for its steel and gold construction in 1933, on the reasoning that steel supplies the structure and gold supplies the color. Gem-set bezels paired with unset dials are the less common of the two arrangements, since most buyers specifying stones on the case go on to specify them on the dial as well. Within the generation, 278343RBR is the steel and yellow gold reference with a diamond-set domed bezel. Two-tone fell out of favor across the industry through the 2000s and returned over the past decade, and the Datejust carried it continuously rather than dropping and reviving it. White is one of only two grounds at this reference offered without stones on the dial, champagne being the other, and it is the only one of the seven that never appears set at all. The remaining five exist in set form alone.
The buyer for this wants the decoration held at the perimeter. A set dial changes what the watch is every time it is read, and a set bezel does not, so the face stays a formal white Roman dial and the stones live entirely at the edge of vision. That produces a watch that reads as a dress piece from directly above and as a decorated one from any other angle, which is a range the fully set configurations on this reference cannot offer. It is also the most legible dial here, resolving instantly in any light, and on the Oyster it stays practical enough to be worn without ceremony. Buyers weighing it against the plain-bezel version of the same dial are deciding whether the watch should announce anything at all. Six of the seven grounds here put stones on the face, so the plain white dial is a step away from what the reference mostly builds, and both bracelets remain open on it.
