The dressiest way to wear a bright color is to put it on the finest bracelet available. Reference 278240 is the 31mm Datejust in stainless steel with a domed bezel, and this configuration pairs a bright blue dial and applied Roman numerals with the Jubilee bracelet. Saturated blue is the most assertive dial the reference offers, and the Jubilee is the most considered bracelet it offers, so the watch ends up emphatic at the face and refined at the wrist rather than committing to either register. That combination is what separates it from the same dial on an Oyster, which reads as a colored tool watch instead.
The Jubilee's five rows across the width alternate polished narrow center links with brushed wider outer ones, and on an all-steel bracelet that alternation is a matter of finish rather than of material, so the effect depends entirely on how light falls across it. Rolex uses a more corrosion-resistant steel grade than the industry standard, harder to machine and holding a polish that runs cooler than softer alloys, which is what keeps that finish contrast legible after decades rather than years. The bracelet also carries roughly twice the component count of the Oyster across the same width, which is why it articulates more finely and follows a wrist more closely. The dial is saturated blue lacquer applied opaque, so there is no depth to the surface and no sense of looking into it, and the density means any variation in thickness would show as a change in tone, which makes uniformity across the diameter the whole of the execution. The Roman numerals are applied white gold and faceted, drawn for this case size rather than scaled from a larger one, and a full sequence occupies a considerable share of a 31mm dial. The domed bezel above is smooth and unbroken, the quietest shape the model is offered with. The date at three displaces the numeral that would otherwise sit there, on a matched disc. The case flanks are polished while the top surfaces are brushed, a division that survives decades of wear only because the steel is hard enough to hold both finishes distinctly, and against a bracelet doing the same thing across five rows the whole watch reads as a study in two finishes of one material.
The date is the only indication beyond the time, and a single aperture is what allows a full Roman sequence to fit. Rolex matches the date disc to the dial rather than leaving a white window in a saturated surface. The Cyclops lens above it has been part of the Datejust since 1953. 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 crown screws down against the case, and the Jubilee closes with a concealed clasp folded away inside the links. The crown screws down against a threaded tube set into the case, and that join is what has to be re-seated correctly every time the date is corrected, which is the one piece of routine care the watch asks of an owner.
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. Strong dial colors are recent within the model, which ran on silver, white, champagne and black for most of its history, so this configuration pairs the oldest bracelet the watch has worn with one of the newest dials it has been given. Blue has become the color Rolex reaches for first when introducing a new dial treatment. Within the generation, 278240 is the steel reference with a domed bezel. Steel has also carried the colored dials in greater numbers than the precious metal references, since a buyer spending less on the case is generally more willing to take a position on the dial, and the strongest colors in the range consequently tend to appear on steel first. Seven grounds are built at this reference, none of them carrying stones, and all of them sit in the same steel case on a choice of two bracelets, which leaves the color as the whole of the decision.
The buyer for this wants the color and does not want the watch to look casual because of it. On the Oyster a bright blue Datejust reads as something to be used, and the Jubilee moves it toward something chosen, which is a considerable shift for a bracelet change on a watch where every other element is identical. It is also the more comfortable of the two at this size, following a small wrist more closely, so the dressier option is again the more wearable one. Buyers who like the dial but found the Oyster version too plain around it tend to end up precisely here, and the pair attracts genuinely different people rather than the same person weighing two similar things. Between the two the Jubilee is also the version more often kept, since a watch that reads as chosen tends to be treated as a decision rather than as equipment. It is also the configuration here that most rewards being seen in person, since the interplay of finishes across the case and bracelet is exactly what a photograph flattens.
