A subtly improved – and enlarged – update to Jaeger-LeCoultre’s staple watch, the Master Control.

Sports fans will remember the principle of “marginal gains”. It was all the rage a few years ago, when we gloried in Team GB’s dominance of the world of cycling under the guidance of fanatical improver Sir David Brailsford. The idea is simple: if you improve a multitude of factors even by just one per cent, the sum total amounts to a step change in quality that puts you at the top of the game.

It’s an idea to mull over when considering Jaeger-LeCoultre’s new Master Control Date. Jaeger-LeCoultre created this range in 1992, and this represents its biggest overhaul since it gained a new movement in 2005. Yet there has been no drastic rethinking of the concept, or radical shift to embrace newfangled materials: it remains a simple, round watch in stainless steel that gives you the time and date, no more. But everywhere you look? Improvement.

Take the movement: this is Jaeger-LeCoultre’s real area of expertise (the maison has produced more than 1,200 different in-house calibres in its near-200-year history). The escapement has been redesigned and now uses silicon parts for reduced friction; the mainspring barrel has also been reworked to give the watch a longer power reserve (70 hours) without making the watch itself any thicker. It’s hard to overstate the forensic attitude JLC has taken to tweaking – we’re talking about tiny details such as changing what certain screws are made from and upgrading the lubricating oils…

It’s intensely nerdy, technical stuff, but the end result is simple and tangible: a more efficient watch that runs for longer and is more reliable. It’s no coincidence that Jaeger-LeCoultre was the first major watch brand to up its manufacture warranty to eight years.

The new Master Control range has also grown, by one millimetre. It’s an interesting move – this kind of watch is often seen as having a sweet spot at 38mm to 39mm. And while this isn’t a big change, it’s an indication that JLC isn’t as convinced by the resurgence of smaller watches that we’ve seen at a few other brands.

Along with the resizing, the Master Control has had its proportions finessed as well. The older model had a thicker bezel, so even though this is larger, it appears slightly less blocky. Crucially, it has remained thin: at 8.8mm, it is only a tiny bit thicker than the brand’s own Master Ultra Thin time-only models, which is pretty impressive for a watch that isn’t overtly marketed as a slimline reference.

Twice in three weeks we’ve focussed on such “entry level” pieces from top luxury brands and there’s a reason for that. These are the foundations that entire collections are built on, so if these are good, there’s a high chance the more complicated versions will be, too.

Not only that, when there is no tourbillon to dazzle or bold new design language to introduce; every element on the watch has to work that little bit harder to impress. Watches like this sometimes get overlooked in favour of showier models but, to me, they are an excellent barometer for a brand’s progress.

Jaeger-LeCoultre Master Control Date Automatic 40mm, ref. 4018420

Materials: Stainless steel and leather

Diameter: 40mm

Height: 8.8mm

Water-resistance: 50m

Power reserve: 70 hours

Price: £6,000