Everything on this watch is the same shade except the diamonds. 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 carries a champagne dial with diamond markers in gold settings and no numerals, on the Oyster bracelet. Champagne was developed to sit against yellow gold. The settings holding the dial stones are yellow gold, and the bezel the outer stones sit in is yellow gold. Steel appears only at the case flanks and the outer bracelet links, where it stays at the perimeter and out of the way. What that leaves is a watch in which the diamonds are not competing against a color at all, only against a tone they very nearly match.
Working in a single tone puts the whole burden on finish, and this configuration answers it with three different treatments of the same metal. The bezel is domed and polished, so it throws a hard highlight that travels as the wrist turns. The dial is champagne, a warm metallic ground applied flat and even, which returns light softly and without a hot spot. The marker settings are polished gold at a much smaller scale, reading as points rather than as areas. One metal, three behaviors, and the eye separates them by finish alone rather than by color. That is a harder effect to bring off than a contrasting dial, and it is the reason this version rewards being seen in person more than it rewards a photograph. Rolex keeps the settings low against the dial, since a raised marker on a 31mm face interferes with the hands before it adds anything, and it holds those settings to the same height as the date frame so the dial reads as one plane with elements standing off it. The case is steel with gold at the bezel, crown, bracelet center rows, marker settings and hands, all solid rather than plated. The Oyster bracelet is three broad flat links, brushed on top with polished flanks, closing on a concealed clasp.
The date is the only thing the watch does beyond telling the time, and on a champagne ground it is the one place with real contrast. Its disc is matched to the dial rather than left pale, and against a warm metallic surface the magnified numeral carries about as much definition as a date display can be given without breaking the tone. The date changes instantly at midnight rather than rolling through the hours on either side, the function the model introduced in 1945 and takes its name from. Above the aperture the Cyclops lens has been fitted since 1953 and enlarges the numeral roughly two and a half times. Correction is made at the winding crown on a dedicated position, without moving the hands and without anything to press at the side of the case. The movement is self-winding with a power reserve of approximately 55 hours, a figure that belongs to a movement built for a case this narrow rather than carried down from a wider one, since both the barrel and the rotor are smaller and each does proportionally less work. The crown screws down against the case. Worn regularly the watch never needs setting, and left aside for two days it does.
The Datejust arrived in 1945 as the first self-winding wristwatch to show the date in a window, and it has been in production ever since. The 31mm case sits between the 28mm Lady-Datejust and the 36mm original, and 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 the steel does the structural work and the gold does the visible work. Champagne is among the oldest dial tones the model has carried and has never left the catalogue, which is unusual, since most grounds rotate in and out over a generation or two. Set markers on a champagne ground are similarly long-running, and the two together under a gem-set bezel are close to the original idea of a decorated Datejust, one Rolex has continued rather than revived. Within the generation, 278343RBR is the steel and yellow gold reference with the diamond-set domed bezel, and champagne appears on it in two forms: this one, and a plain version with applied markers and no stones in the dial at all. The difference between those two is smaller in a photograph than it is on a wrist. In the metal the set version reads as a considerably older idea of the model.
The buyer here wants a watch that is fully specified without being loud, and this is the version of the reference that manages it. A colored dial announces itself and a bright white ground creates hard contrast, but champagne sits at the same tone as the gold around it, so the whole watch reads as a single object rather than as a case with a dial set into it. The stones then carry the entire job of providing interest, and they do it at a small scale. The Oyster bracelet holds the same line, being the plainer of the two options and built to be worn daily rather than saved for occasions. There is a period argument here as well, since a warm dial with gold settings under a set bezel is the configuration two-tone Datejusts were known for through the decades when they were most common. Buyers who came in wanting something that looks expensive close up and unremarkable across a room usually stop at this one and go no further. The thing to check in person is how the marker stones sit against the ground in low light, where a warm dial gives them the least help.
