Jaeger-LeCoultre Slims Down the Master Ultra-Thin Power Reserve

Thanks to an upgraded movement.

Jaeger-LeCoultre begins the new year with an enhanced version of one of its signature watches, the Master Ultra-Thin Power Reserve. While largely maintaining the design of the existing model, the new variant has a new look with a pink gold case, more cohesive styling and most notably, an upgraded movement with silicon parts and a longer power reserve.

Initial thoughts

Although present in the Jaeger-LeCoultre (JLC) catalogue for over two decades in one form or another, the Master Ultra-Thin Power Reserve doesn’t get as much attention as its Master collection siblings, not to mention the famed Reverso. However, given the brand’s historical status as a vertically-integrated movement maker, the new Master Power Reserve plays to the JLC’s strengths since it retains the familiar design while installing all-new mechanics in the form of the cal. 938. 

The update is a practical one, since the new calibre has a longer power reserve of three days. However, the update is not an accessible one from a price perspective, since this enhancement is currently exclusive to this boutique-only pink gold version and has not been extended to the steel model. The update will almost certainly make its way into the more affordable model some time in the future, so it’s a matter of waiting.

JLC was historically known for its value-oriented pricing, an edge that has been dulled somewhat in recent years as its prices have crept upwards. This watch illustrates that, even if it is still priced comparably to similar watches from the competition. The Master Ultra-Thin Power Reserve is priced at US$21,200, which is within the typical range for such a watch in pink gold but it costs double the steel variant. 

A sleeker design and upgraded movement

The Master Ultra-Thin Power Reserve is one of the more elegant models in the current catalogue of the Le Sentier manufacture. Sometimes known as the Master “Réserve de Marche” (French for “power reserve”), the model has a useful combination of functions on a concise dial: date, small seconds, and power reserve indicator. The date is indicated on a sub-dial, instead of a window, so it is slightly less legible than average, but it results in a more balanced dial layout.

The Master Ultra-Thin Réserve de Marche from 2017

Although the dial preserves the traditional layout of the model, it now features a more sophisticated design thanks to various adjustments to the details.

The numerals of the power reserve scale and date track are now positioned within their respective sub-dials, instead of being arranged on the outer periphery of each register. “Réserve de Marche” has also been eliminated, resulting in a cleaner dial overall, although the seconds register now gains the unnecessary “Automatique” label.

And the dial colour also gets more interesting. It remains a dark blue, but the dial and sub-dials sport a gradient finish, giving it a more nuanced hue.

A red accent on the power reserve adds a bit of colour to the dial

The main highlight of this release is the upgraded cal. 938, a variant of the brand’s workhorse automatic movement found in many of its dress watches.

Compared to its predecessor that ran for 43 hours, the cal. 938 has a power reserve of 70 hours. This improvement comes about from of a redesigned mainspring barrel and the integration of silicon escapement components that enhance energy transmission in the going train by minimising friction between the parts.

The 18k pink gold case has the same 39 mm diameter as the earlier generation predecessor, but it has been reshaped with sleeker lugs. More importantly, it is now thinner at 8.95 mm in height — an almost 1 mm reduction in thickness over the outgoing model.

Key facts and price

Jaeger-LeCoultre Master Ultra-Thin Power Reserve
Ref. Q137258J

Diameter: 39 mm
Height: 8.95 mm
Material: 18k pink gold
Crystal: Sapphire
Water resistance: 50 m

Movement: Cal. 938
Functions: Hours, minutes, small seconds, date and power reserve indicator
Winding: Automatic
Frequency: 28,800 beats per hour (4 Hz)
Power reserve: 70 hours

Strap: Alligator leather strap

Limited edition: No
Availability: At Jaeger-LeCoultre boutiques only
Price: US$21,200; or 30,300 Singapore dollars

For more information, visit Jaeger-lecoultre.com.


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