Rolex Datejust 31 Yellow Rolesor — Dark Mother-of-Pearl Diamond Dial | Ref. 278243

Introduced at Baselworld 2019 as part of Rolex's comprehensive Datejust 31 refresh, reference 278243 brought the smaller Datejust format into alignment with the mechanical and aesthetic standards established by the full 36mm reference. This example, cased in Yellow Rolesor — an Oystersteel monobloc case complemented by 18ct yellow gold crown, bezel, and bracelet elements — presents a dark mother-of-pearl dial set with diamond hour markers: a configuration that distils the watch's competing impulses toward restrained classicism and jewelled opulence into a single, coherent composition. The dark nacre shifts between deep grey-green and midnight blue depending on incident light, providing endless visual interest.

The movement at the heart of this reference is the Calibre 2236, a manufacture calibre developed specifically for Rolex's mid-size and ladies' references. Its silicon Syloxi hairspring offers immunity to both magnetic fields and the thermal variations that challenge conventional alloy springs, while its Paraflex shock absorber provides outstanding protection against mechanical shock. The bidirectional Perpetual rotor winds through ordinary wrist movement, sustaining the approximately 55-hour power reserve. Chronometer certification from the COSC guarantees daily precision within -4/+6 seconds — and Rolex's own testing elevates performance to the Superlative Chronometer standard of -2/+2 seconds.

The domed 18ct yellow gold bezel introduces sculptural relief to the case profile, while the Yellow Rolesor Oyster bracelet — 904L steel and 18ct yellow gold in Rolex's flat three-piece link format — anchors the watch securely to the wrist via the Oysterclasp and five-millimetre Easylink extension. Sapphire crystal with Cyclops date lens completes a specification that places this 31mm Datejust among the most technically accomplished mid-size dress watches available from any manufacturer.