Everything on this watch below the bezel could belong to a man's watch, and the bezel could not. Reference 278289RBR is the 31mm Datejust in solid white gold with a bezel set with diamonds, and this configuration pairs it with a dark grey dial and applied Roman numerals, on the President bracelet. A sober neutral ground, the most formal marker set Rolex fits, a white metal case that gives away nothing about its material, and then a ring of stones around the outside. The dial is entirely serious and the bezel is entirely decorative, and Rolex makes no attempt to reconcile them.
That refusal is what makes the configuration work rather than a compromise. Roman numerals occupy more of a dial than any other marker set Rolex offers, and the brand draws them for each case size rather than scaling a single set across the range, so the ones fitted here are proportioned for a 31mm dial rather than inherited from a larger one. Applied in white gold and faceted, standing off the surface rather than printed onto it, they read against a mid-tone grey by a combination of their own brightness and the shadow they throw, which is a more balanced relationship than they achieve on either a pale or a black ground. The dial is an opaque lacquer laid down in several thin coats so it holds one value from any angle, matte where the case is variously polished and brushed, and dark grey is the most neutral of the deep colors offered here, cooler than chocolate and considerably lighter than aubergine. The case is solid white gold rather than a two-metal combination, uniform from the lugs through the bracelet and considerably denser than steel, so the watch carries noticeably more mass than its size suggests. 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. The bracelet is the President, semi-circular three-piece links with a concealed clasp folded away so completely that the bracelet appears continuous from every angle, tapering from the lugs toward the clasp so the mass sits forward on the wrist. The date at three displaces the numeral that would otherwise sit there, on a disc matched to the dial. The hands are polished white gold and drawn short of the numerals so they cross the dial without appearing to touch them, which on a full Roman sequence is a tighter tolerance than it sounds.
Rolex matches the date disc to the dial rather than leaving a white window in a darker surface, which decides whether the aperture belongs to the watch or interrupts it, and a single aperture is what allows a full Roman sequence to fit at all, since a second window would leave no room for twelve numerals on a dial this size. The Cyclops lens above it has been part of the model 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 Datejust introduced in 1945 and the one it takes its name from. Correction runs through the winding crown without moving the hands, and nothing the watch asks for requires a tool. The movement is self-winding with a power reserve of approximately 55 hours, an engineering result on a movement built to fit a 31mm case rather than a figure carried down the range, since a smaller barrel has less room to store energy and a proportionally smaller rotor gathers less of it. The rotor winds in both directions rather than only one, which lets a movement this size keep itself running on the wrist movement of an ordinary day. The crown screws down against the case.
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. Roman numerals have been offered across most of the model's history and have never been the volume choice, and dark grey has appeared across several generations without ever being the volume seller either, so neither element is recent and neither is common. Solid gold references are built in far smaller numbers than the steel and two-metal ones, and the white gold versions in smaller numbers again. The President bracelet was designed in 1956 for the Day-Date and appears on the precious metal Datejust references as a borrowing rather than an inheritance. Within the generation, 278289RBR is the solid white gold reference with a diamond-set bezel. Grey reached the precious metal references at the same time as the steel ones rather than later. Within this reference grey is one of three grounds offered both plain and set, and its set form exists in two arrangements, one with diamond hour markers and one with a large Roman six carrying eleven stones.
The buyer for this wants the watch to be read as serious first and expensive second. Solid white gold and a set bezel could easily produce something purely decorative, and a grey Roman dial pulls hard in the other direction, so the object ends up genuinely difficult to categorize, which for a certain kind of buyer is the whole appeal. It is also among the most legible dials on the reference, resolving instantly in any light where the nacre, gradient and gem-set configurations ask for a second look. Between this and the index version of the same color, the numerals are what make the restraint look deliberate rather than merely quiet, and buyers weighing the two usually decide on that alone. It is the version a buyer keeps rather than trades. Ten grounds are available at this reference and six of them carry stones on the face, so choosing the plain grey means passing over most of what is on offer.
