Oyster Perpetual Lady-Datejust in 18 ct yellow gold, bezel set with 46 brilliant-cut diamonds, white mother-of-pearl dial set with 10 diamonds. Image: Rolex

In the realm of watches, the Rolex Oyster Perpetual Lady-Datejust is a legend. It was first presented in 1957, at a period when women were evolving and adopting new, more active lives. They discovered a new sense of independence and a desire to have more control over their lives and better manage their time. The Lady-Datejust was created by Hans Wilsdorf, the founder of Rolex, who knew what the modern lady desired.

Women have always played an important role in Rolex’s history. They have inspired the invention and development of extraordinary watches that will help their quest for empowerment from the brand’s inception. The Lady-Datejust is a tribute to people who take the initiative. It is the epitome of perfection, blending traditional grace with technical prowess.

The Lady-Datejust has a 28 mm Oyster casing that is certified waterproof to a depth of 100 meters (330 feet) and is made of Oystersteel or 18 ct gold. With a Cyclops lens at 3 o’clock over the date, the sapphire crystal is extremely scratchproof. There are several dial modifications available in a variety of materials, colors, markings, and patterns, giving the discriminating woman a variety of possibilities to personalize her watch and make a statement.

A Watchmaking Milestone

“Ladies desire the best of all worlds: a little watch with a precise movement,” Hans Wilsdorf famously said of his ongoing endeavor. The more precise a watch is, the more difficult it is to produce it.”

This is why the Lady-Datejust was “motivated by daring,” since producing such little accurate movements in the twentieth century was a tremendous technological challenge. Rolex has made several changes to the core of the Lady-Datejust since its launch. It is now equipped with calibre 2236, a self-winding mechanical movement designed and produced solely by Rolex.

Calibre 2236

Calibre 2236. Image: Rolex

Introduced in 2014, calibre 2236 is a self-winding mechanical movement created and manufactured solely by Rolex, with exceptional precision, power reserve, shock and magnetic field resistance, convenience, and dependability. This movement has a lot of patents and is a perfect showcase of technology. Let’s take a closer look at this cutting-edge watchmaking mechanism.

The Heart Of The Lady-Datejust

Those who are interested in watches know that the oscillator is the ‘keeper of time’ in mechanical watches, preserving the precision of the watch through interactions between the balance wheel and the hairspring. The oscillator of calibre 2236 includes a balancing wheel with variable inertia that is adjusted exceptionally precisely by gold Microstella nuts and is kept securely in place by a height-adjustable traverse bridge that allows for highly solid placement for increased shock resistance. The oscillator is also installed on Rolex’s high-performance Paraflex shock absorbers, which have been created and patented.

Paraflex. Image: Rolex

A movement’s hairspring is a fragile component that is susceptible to environmental disturbances that might degrade the oscillator’s function. Magnetic fields, temperature variations, and shocks all cause the oscillator to malfunction. Rolex created the new Syloxi hairspring to bring a second different paramagnetic balancing spring technology to its portfolio of high-performing hairsprings, alongside the blue parachrom hairspring, to give better stability in the face of severe disruptions.

Rolex manufactures the Syloxi hairspring entirely in-house, using a silicon and silicon oxide composite, a combination of materials with thermo-compensating and paramagnetic properties that allow the hairspring to maintain its high precision even when exposed to temperature changes and magnetic interference.

The hairspring is manufactured with a proprietary design that optimizes its isochronism and consequently the regularity of the oscillations of the balance wheel-hairspring assembly using deep reactive ion etching technology (DRIE). The hairspring’s variable pitch and thickness coils, optimized along the length of the hairspring, guarantee continuous development in all situations, adjusting for gravity’s effects. A hairspring is attached to the balancing staff and bridge using a revolutionary flexible collet, removing the need for glue and maintaining the hairspring’s inner end exactly perpendicular, level, and self-centring.

Syloxi hairspring. Image: Rolex

Looking down the hairspring, one can observe that the Syloxi ends in a more rigid, strengthened crescent-shaped section that provides a two-point attachment to the traversing balancing bridge, guaranteeing that the hairspring is completely centred, flat, and free of any residual mechanical stress in its active zone.

Rolex was able to optimize the beat adjustment by utilizing a Paraflex shock absorber with fluting for this reason, which is also the signature of Syloxi-equipped calibres. This feat of precise engineering gives the Syloxi with greater temperature stability, up to ten times more accuracy than a regular hairspring in the event of a shock, and more resistance to magnetic fields. The calibre 2236 also has a paramagnetic nickel-phosphorus escape wheel, which increases its resistance to magnetic forces.

The Lady-Datejust, like other Rolex watches, is covered by the Superlative Chronometer certification, which Rolex revised in 2015. A Rolex Superlative Chronometer has an accuracy of 2/+2 seconds per day — the rate variation permitted by the brand for a completed watch is much lower than the rate deviation recognized by COSC for formal certification of the movement alone.

Perpetual rotor. Image: Rolex

Each calibre 2236 has a self-winding module through a Perpetual rotor, which assures continual winding of the mainspring by harnessing wrist motions to produce steady energy. This provides a power backup of about 55 hours. Calibre 2236, like other Rolex movements, is manufactured entirely in-house by Rolex. The iconic Lady-Datejust, a watch that embodies Rolex principles, has been a byword for style and technological excellence since its debut, recognizing individuals who dare to lead the way.