Datejust 31 Stainless Steel / Oyster / Black - Roman

About This Watch

The Rolex Datejust 31, in its 2020 iteration, embodies the enduring balance of tradition and refinement that has defined the collection since its introduction in 1945. This particular model, with its black dial and polished stainless steel case, captures the essence of understated sophistication, marrying the Datejust’s legacy of timeless design with contemporary precision. The dial’s deep black finish is accented by luminous Roman numerals and slender stick hands, their contrast against the matte surface evoking a sense of quiet authority. The domed stainless steel bezel, paired with the Oyster case’s seamless construction, reinforces the watch’s robust yet elegant character, while the sapphire crystal ensures clarity and durability. At its heart lies the Caliber 2236, a self-winding movement developed entirely in-house by Rolex, renowned for its reliability, precision, and the hallmark craftsmanship of the brand. The 31mm case diameter, paired with a 16mm lug width, offers a proportionately balanced presence on the wrist, ideal for those who seek a watch that is both discreet and unmistakably prestigious. The 100-meter water resistance and closed case back further underscore its practicality without compromising its aesthetic restraint. This watch is for the discerning individual who values heritage, craftsmanship, and the quiet confidence of a timepiece that requires no introduction. It suits the boardroom, the gala, or the quiet moments of contemplation—worn as a testament to legacy and the enduring appeal of a watch that has remained, for over seven decades, a benchmark of excellence.

In Context

At 31 mm it is small by current standards, in the range most wristwatches occupied before cases began growing through the 1990s. The case back is closed, so the movement stays out of sight, and the sapphire crystal will resist everything short of deliberate abuse. 100 m is genuine swimming resistance — more than the shape of this watch suggests it would need.

The movement winds itself from the motion of your wrist. 55 hours of reserve is enough to set it down on Friday evening and find it still running on Monday. At 28,800 vph the seconds hand advances 8 times a second.

278240-0001 is one of 18 executions of the 278240 base reference. Underneath they are the same watch; what separates this one is a black gloss dial and a stainless steel case. Introduced in 2020.

Rolex

Black · Stainless Steel

278240-0002 · 31 mm

Rolex

White · Stainless Steel

278240-0003 · 31 mm

Rolex

White · Stainless Steel

278240-0004 · 31 mm

Rolex

Silver · Stainless Steel

278240-0005 · 31 mm

Rolex

Silver · Stainless Steel

278240-0006 · 31 mm

Rolex

Pink · Stainless Steel

278240-0007 · 31 mm

Rolex

Pink · Stainless Steel

278240-0008 · 31 mm

Rolex

Grey · Stainless Steel

278240-0009 · 31 mm

+ 9 more variants in this family.

The 2236 is the Rolex movement inside more watches in this library than any other: 907, in the 28 mm Lady-Datejust and the 31 mm Datejust 31. It was the first Rolex caliber with a silicon hairspring. Introduced in 2014 in the Pearlmaster 34, it is a 20 mm automatic with a date, 31 jewels, a 55-hour reserve and a beat of 28,800 vph, certified by the COSC and then tested again by Rolex after casing to the Superlative Chronometer tolerance of two seconds a day. Its distinction is the Syloxi hairspring: silicon, immune to magnetism, etched to a patented geometry that keeps the spring concentric in every position, and paired with Paraflex shock absorbers. The larger Rolex calibers kept the Parachrom alloy spring; Syloxi did not reach a men's movement until the 7140 of 2023. The [2236 piece](/blog/the-rolex-2236-the-most-common-movement-in-this-library) sets out that history. In the library it powers 488 [Datejust 31](/brands/rolex/datejust-31) references, the seven-digit 2782xx generation of 2020, 399 [Lady-Datejusts](/brands/rolex/lady-datejust) of the 2791xx generation of 2015, 15 [Pearlmasters](/brands/rolex/pearlmaster) and 5 [Yacht-Master 37s](/brands/rolex/yacht-master). The [2235](/calibers/rolex-2235) is the 48-hour movement it replaced, the [2232](/calibers/rolex-2232) its no-date sibling for the Oyster Perpetual, and the [3235](/calibers/rolex-3235) its counterpart in the 36 mm and 41 mm cases.

906 other watches in the library run the Rolex 2236.

Rolex

Lady-Datejust 28 Rolesor Everose Diamond / Oyster / MOP

279381RBR-0014 · 28 mm

Rolex

Lady-Datejust 28 Rolesor Rose Diamond / Jubilee / MOP

279381rbr-0013 · 28 mm

Rolex

Lady-Datejust 28 Rolesor Yellow Domed / Oyster / MOP

279163-0014 · 28 mm

Rolex

Datejust 31 Stainless Steel / Yellow Gold / Diamond / Black MOP / Oyster

278383RBR-0023 · 31 mm