Datejust 31 Stainless Steel / Jubilee / Black - Roman

About This Watch

The Rolex Datejust 31, introduced in 2020, embodies the enduring refinement of a collection first conceived in 1945 as a timepiece that could seamlessly transition from boardrooms to evening engagements. The reference 278240-0002, with its 31-millimeter stainless steel case and domed bezel, strikes a balance between modern proportions and the timeless elegance that defines the Datejust lineage. A matte black dial, framed by a polished stainless steel bezel, is adorned with Roman numerals and paired with sleek stick hands, creating a composition that is both legible and subtly dramatic. The Jubilee bracelet, a hallmark of the collection, complements the case’s understated sophistication, its five-link design offering a refined interplay of curves and symmetry. At its core, the watch houses the in-house automatic caliber 2236, a movement certified as a chronometer for precision and reliability. With a power reserve of approximately 55 hours and a date display at the 6 o’clock position, it reflects Rolex’s commitment to mechanical excellence without ostentation. The sapphire crystal, paired with a water resistance rating of 100 meters, ensures durability without compromising the watch’s delicate aesthetic. This timepiece is for those who value heritage and discretion, seeking a watch that speaks volumes through craftsmanship rather than excess. It suits the discerning individual who appreciates the quiet confidence of a well-worn patina or the polished restraint of a first-time acquisition—equally at home in the quiet moments of daily life or the grandeur of a formal occasion.

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.

278240-0002 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

278240-0001 · 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