The green on this watch exists only in the space between two sets of stones. 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 an olive green dial with diamond markers in gold settings and no numerals at all, on the Oyster bracelet. Diamonds run the full circumference outside the crystal and stand at every hour position inside it, which leaves the ground occupying a band between them and the open area at the middle of the dial. That is a smaller share of the watch than any other olive configuration on the reference gives it. The green is still what the watch is called, and it is no longer the first thing seen.
The gold settings are what hold this arrangement together rather than letting it read as two unrelated groups. Each dial stone sits in its own solid gold surround, and that surround is the same metal as the bezel the outer stones are set into, so the eye links the inner and outer groups through the gold rather than through the diamonds alone. Without those settings the markers would float on green with nothing tying them back to the case. Olive green is applied as an opaque lacquer in successive thin coats, dark enough to swallow reflections and even enough not to band across the curve of the dial, and it is the deepest ground offered on the reference. Deep grounds suit set markers, since the stones separate from them completely and need no help from a numeral to be found. Rolex keeps the settings low and tight against the dial, because a raised marker on a case this narrow begins to interfere with the hands before it begins to look generous. The case is steel with gold at the bezel, crown, bracelet center rows, marker settings and hands, all of it solid. The Oyster bracelet is three broad flat links, brushed across the top with polished flanks, closing on a concealed clasp. It is the plainer of the two bracelets and the one that leaves the case as the widest object on the wrist.
Removing the numerals leaves the marker ring running unbroken except at three, where the date window interrupts it, and a single aperture is the most a dial arranged this way can absorb before the pattern stops reading as a ring. The date advances instantly at midnight rather than creeping through the hours around it, the function the Datejust introduced in 1945 and took its name from. Its disc is matched to the olive ground so the window sits into the dial rather than on top of it, and the frame is proportioned for this diameter instead of scaled from a larger one. Above the window the Cyclops lens, part of the model since 1953, enlarges the numeral roughly two and a half times, which matters more here than on a dial with numerals because there is no other printed element on the face to establish a reading distance. Correction is made through the winding crown at its own position, leaving the hands untouched. The movement is self-winding with a power reserve of approximately 55 hours, sized for this case rather than inherited from a wider one, since both the barrel and the rotor are smaller and each does proportionally less. The crown screws down against the case, and the bracelet folds shut on itself.
The Datejust has been in production since 1945, when it became the first self-winding wristwatch to show the date through a window on the dial. The 31mm case was placed between the 28mm Lady-Datejust and the 36mm original for buyers who wanted neither, 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. Set markers without numerals are the older of the two gem-set dial approaches on the model. Rolex was fitting them long before it began setting stones into numerals, and they have never left the catalogue. What has changed is the ground beneath them, which for most of that history was silver, champagne or black, and only recently a saturated color. Within the generation, 278343RBR is the steel and yellow gold reference with a diamond-set domed bezel, and the olive dial appears on it both with markers set this way and with a Roman sequence whose large numeral at six carries the stones instead. Gem-set bezels and gem-set dials are also handled differently in service, since a bezel can be worked on without opening the case. That difference tends to matter to owners only years later.
This is the configuration for a buyer who wants the ornament even on both sides of the crystal. The bezel and the markers use the same stone in the same metal at two different radii, and on a dark ground they read as one continuous system rather than as a dial that has been decorated and a bezel that has been decorated separately. Nothing on the watch argues with anything else. The Oyster keeps the wrist plain underneath it, which is what allows the head to carry that much brightness without the whole watch tipping into display. Olive green is doing quieter work than its name suggests here, closer to a dark neutral than to a statement, and buyers often choose it over black for exactly that reason: it gives the stones a ground as deep as black without the flatness. Those who tried the Roman version and found the single set numeral unbalanced generally end up here. Those who wanted the ground itself to lead generally do not. It is also the easier of the two to wear without thinking about, since a marker ring gives the eye nothing to align and the watch simply reads as bright.
