Change the bracelet and this becomes the most conventional watch in the reference. Reference 278344RBR is the 31mm Datejust in a combination of stainless steel and white gold with a domed bezel set with diamonds, and this configuration pairs a white dial and applied Roman numerals with the Jubilee bracelet. White Romans on a Jubilee is the arrangement the Datejust has worn longest, and the only things separating this from a watch that could have been sold decades ago are the diamond-set bezel and the fact that the second metal is white rather than yellow. Nine grounds are built at this reference and white is one of the four that never carry stones on the dial.
The Jubilee was introduced in 1945 for the original Datejust, which makes it the bracelet native to the model rather than an option added later, and its five links across the width put white gold center rows between steel outer links. Because those two metals sit so close in color the alternation reads as a change of finish rather than of material, which is the defining characteristic of a white two-tone watch and the reason it passes for single-metal until examined closely. The bezel above is white gold set with diamonds, covering most of the only surface where the distinction would otherwise be legible. 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, and it offers nothing to hide behind, so any imprecision in how a numeral is planted shows at once. The Roman numerals are applied white gold and faceted, drawn for this case size rather than scaled from another. The date sits at three under the Cyclops lens, taking the place of the numeral that would otherwise be there. White gold is also considerably denser than steel, so the bezel here is noticeably heavier than a steel one of the same dimensions, and on a 31mm case that weight sits at the outer edge where it is most felt. It is the one way the second metal announces itself on a watch where it cannot be seen. Rolex casts its own gold in a foundry on its premises, which is unusual in the industry and is the reason the brand can hold an alloy to a consistent color across decades of production. The bezel 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 on a larger bezel of the same design.
Against white lacquer the magnified date is about as legible as a date display gets, and the Cyclops lens has been part of the Datejust since 1953. A single aperture is what allows a full Roman sequence to fit at all. 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 its name. Correction runs through the winding crown without advancing the hands, hand winding uses the same crown with no separate position to learn, 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 inherited 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. A movement of this size gathers less from the same wrist movement than a larger one, so the watch prefers regular wear to rotation. Correction takes seconds and requires no tool, which on a watch meant to be worn constantly matters more than the reserve figure itself.
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. White with Roman numerals has existed in some form across every generation of the model, and on a Jubilee it is as close to the archetype of the Datejust as the current catalogue gets. Roman numerals themselves have never been the volume choice, which is part of why they still read as considered. Within the generation, 278344RBR is the steel and white gold reference with a diamond-set domed bezel. Gem-set bezels with unset dials are also a smaller share of production than the reverse, since most buyers specifying stones on the case go on to specify them on the dial as well, which makes this arrangement less common than the conventionality of the rest of the watch would suggest. White is one of seven grounds this reference offers unset, and one of four with no set counterpart on the roster.
The buyer for this wants the familiar watch with one thing added. Everything except the bezel is the version the model has worn for most of its life, and the stones are the single departure, which makes them read as an addition to a known object rather than as part of a new one. That is a different effect from a gem-set dial, which changes what the watch is rather than decorating what it already was. It is also the configuration here most likely to be recognized as a Datejust by someone who knows nothing about references, and for a good many buyers that recognition is the point. It is the configuration here that asks the least explanation of anyone looking at it, and the one most likely to still be worn in thirty years without having been thought about once. It is one of twelve grounds the reference builds and the plainest of them.
