What is the Master Chronometer certification from Omega? And the Coaxial movement?

Franz Rivoira
5 min readSep 20, 2021


The description of the lever escapement

WARNING: this will be a bit technical

Our present-day timepieces represent the evolutions of 500 years of micro mechanics, and the work of thousands innovators who worked to render them more and more precise and dependable.

Among them, there was one — Thomas Mudge — who around 1750 invented a particular form of escapement called the English Lever. Although he seldom used it, as other escapements were more adopted in British horology, like the verge fusée, in time it was refined, especially in Switzerland by Antoine Lechaud, who cooperated with the mosre famous Leschot, modified a bit and named Swiss Lever or Swiss Anchor — from the design of the pallet that resembles a small anchor.

This happened around 1850, and eventually the Swiss lever escapement became dominant in horology. The reasons why are several:

  • The Swiss Lever is a detached escapement. This means that it did not have a continual contact with the balance wheel. less friction = nmore reliability
  • The Swiss lever is self-starting. On the contrary of some others, if for any instance it stops, for example after sustaing a hit, it restarts automatically
  • It has a double impulse, so any error cancels itself out as there is a back-and-forth oscillation

The big issue of the lever escapement is its sliding friction.

How a lever escapement works

As you can see, the movement of the escapement wheel drives alternatively the two jewels placed at the opposite end of the arms of the anchor. And while the wheel is in metal and the jewels are in synthetic ruby, they scrapre like 252,288,000 times per year in a typical watch movement. You can see that “friction” here is an issue.

Unfortunately, from 1750 we have not found anyone who could come up with something better than this. Zero. Until a certain George Daniels came up in 1974 with something: the coaxial escapement.

How a coaxial escapement works

The coaxial escapement reduces the sliding friction over the two endstones by using an additional set of wheels superimposed to the traditional escapement. The two endstones do not slide over the escapement wheel, but are used only to lock on its teeth. This reduces to almost nothing the amount of lubrication needed by these elements.

However, the detractors of this systemsay that while it might lessen the need of lubrication in the escapement and balance, the coaxial does nothing for the rest of the mechanism, which still needs lubrication, and does not impart any significant improvements over the lever escapement, instead being much more complicated technically.

Whatever your school of thought, Omega bought the rights to use the coaxial in 1999 and has used it ever since as an element of distinction in its in-house movements.

Omega timepieces have both a coaxial escapement and a naster chronometer certification

Now let’s talk about the Master Chronometer certification.

As you probably know, a Swiss watch that wants to bear the “Chronometer” label on its dial must be certified by an independent evaluation agency, and until recently, the most used certificator was COSC — Contrôle Officiel Suisse des Chronomètres — which tested the movements under its own-developed specs, such as the famous -4/+6 (but there are an almost endless list of other specs to be respected).

In time, these specs were somewhat too lax for the modern results, so some Maisons wanted more. To put it in very simple terms, Omega’s Master Chronometer certification is a sort of COSC certification on steroids.

Omega took COSC-certified movements, subjected them to even more grueling tests about their performance and characteristics, and made it under METAS-approved specs. METAS is the Swiss Offcial Metrological Institute.

At the end, the watch is tested as to be much more precise than a “simple” COSC, with a 0/+5 daily range (and the list of endless other stats as well).

So, this said. Is all of this stuff useful?

I can tell you what, my friends: in my humble opinion, this is only marketing.

I am a marketing man myself, and know a thing or two about this stuff. In real life, if you need an ultra precise watch for whatever reason, you pick a quartz — maybe the new Citizen-powered 262,144 Hz watches by Bulova, which also offer a sweeping second hand.

The Bulova 262kHz series

They are MUCH more precise than any COSC or METAS certified chronometers at a fraction of the cost.

However, if you instead value the exquisite tradition of mechanical horology and want to place a proper tribute to it and to the watchmakers who rendered it so. And let’s be honest, they look extremely cool.

Omega watches look eminently cool — no doubts about that

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This answer contains promotional references



Franz Rivoira

Book author, global marcomm, luxury and design product pro, specialized in architecture, furniture, design and watches.