Yellow gold is the one case metal that makes olive read warm. Reference 278243 is the 31mm Datejust in a combination of stainless steel and yellow gold with a domed yellow gold bezel, and this configuration pairs an olive green dial set with diamonds and applied Roman numerals with the Jubilee bracelet. Olive contains enough brown to move in whichever direction the metal around it pushes, and yellow gold pushes harder than any other case Rolex builds, so the same lacquer that reads as a cool green in steel or white gold reads here as something closer to khaki. The dial is not a fixed color so much as a color the case is acting on.
The Jubilee amplifies that, because it puts more gold in play than the Oyster does. Its five links across the width alternate yellow gold center rows with steel outer links, and because yellow gold sits nowhere near steel in color the alternation reads as a clear boundary between two materials rather than as a change in finish, which means the wrist is delivering gold to the eye continuously rather than in a single band. The bracelet carries roughly twice the component count of the Oyster across the same width, so it articulates more finely and follows a wrist more closely, and the gold is solid rather than plated or capped, which is why these bracelets hold their appearance across decades where most of the industry's two-tone watches do not. Rolex matches the polish on the center rows to the polish on the bezel so the metal reads as one material distributed rather than as separate applications of it. The olive lacquer is applied in several thin coats to keep the tone even across a curved surface, sitting at the mid-point of the model's tonal range. Against it the diamonds carry moderate rather than maximum contrast, reading as markers first and stones second. The Roman numerals are applied yellow gold and faceted, drawn for this case size rather than scaled from a larger one. The date at three displaces the numeral that would otherwise sit there, on a matched disc. The hands are polished yellow gold and drawn short of the numerals so they cross the dial without appearing to touch them, and Rolex proportions the aperture frame for each case size as well, since a window drawn for a larger dial crowds a smaller one. The lugs are finished so the bracelet meets the case without a visible gap at any angle of articulation.
Rolex matches the date disc to the dial rather than leaving a paler window in a colored surface, 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 model introduced in 1945 and the reason it carries the name it does. Correction runs through the winding crown without advancing the hands, and nothing the watch asks for requires a tool. The movement is self-winding with a power reserve of approximately 55 hours, engineered into a movement built to fit a 31mm case rather than carried down from a larger one, since a smaller barrel stores less energy and a proportionally smaller rotor supplies less of it. The rotor winds in both directions rather than only one. The crown screws down against the case, and the Jubilee closes with a concealed clasp folded away inside the links so the bracelet presents an unbroken outline from every angle. Correction takes seconds and requires no tool, which on a bracelet carrying this many components matters more than it would on a simpler one. 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 Jubilee was introduced the same year for that watch, which makes it native to the model rather than an option added later. 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. Green reached the Rolex catalogue broadly over the past decade and came to this model later than most colors, so the olive configurations pair one of the newest grounds in the range with the oldest bracelet the watch has worn. Within the generation, 278243 is the steel and yellow gold reference with a domed bezel. Gem-set dials have been part of the model for most of its history, and the versions keeping a numeral sequence alongside the stones are the scarcer of the two arrangements. Olive green is one of three grounds on this reference built in two set arrangements, alongside dark grey and silver, and each of the three holds four of the twenty-two rows where every other ground holds two.
The buyer for this should see it before deciding, because it is the configuration on the reference most likely to differ from expectation. Anyone who knows the olive dial from a steel or white gold Rolex will find it a noticeably different color here, warmer and less green, and whether that is an improvement is entirely a matter of taste rather than of quality. It is also the more comfortable of the two bracelet options at this size, following a small wrist more closely than the Oyster does. Buyers weighing the pair are effectively choosing how much gold they want working on the dial, and the Jubilee delivers the most of any option here. It is among the harder configurations on the reference to judge from images, since the color a photograph records depends entirely on how much of the bracelet is in frame. Olive green is never offered plain here.
