Rolex Datejust 36mm Black Dial on Jubilee 126234Overview The Rolex Datejust 36 reference 126234 is the definitive modern expression of the watch that redefined the luxury timepiece in 1945. As the first self winding chronometer to feature an automatically changing date, the Datejust established the blueprint for the classic wristwatch. This current generation reference, introduced in 2019, honors that legacy by maintaining the historically perfect 36mm proportionsa size widely regarded by purists