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When The Chronometer Standard Isn’t Good Enough (Anymore)

Meet the Lebois & Co Venturist with Observatoire Chronométrique+ certification
Robert-Jan Broer
May 07, 2019
When The Chronometer Standard Isn’t Good Enough (Anymore)

For some watch brands, the chronometer certification is just not good enough anymore.  The world has changed since 1973, when the Contrôle Officiel Suisse des Chronomètres, the Official Swiss Chronometer Testing Institute, was founded.

Lebois & Co is proud to introduce to you their new watch, the Venturist. Besides a handsome watch (I will come to that later), this watch has more to it. It has been tested by Timelab and received an Observatoire Chronométrique+ certification.  To understand what this is, we have to recap the regular chronometer certification.

Lebois & Co Venturist


With a chronometer (not chronograph) certified watch, you can trust your watch is very accurate. To be more specific, it has an average daily rate between -4 seconds and +6 seconds. For a mechanical watch, that’s pretty neat to have. In order to have a chronometer watch, or chronometer certified watch to be precise, its movement – or watch – must have been sent to the official Swiss Chronometer Testing Institute for some series of tests. These tests are defined by the COSC and watch brands have little to say about these, they just need to send the movements with a ‘test’ dial and ‘test’ crown. After a while, they will receive the movements back. Those who didn’t pass the test need to be adjusted again, those who did pass the test will be cased. The movements with certification can have the word ‘chronometer’ on the dial. That’s right, it is a protected name to use on a dial.

The current chronometer certification is based on the ISO 3159 standard. This standard was defined (“Lays down the definition of the term “chronometer”, describing the categories, the test programme and the acceptable minimum requirements for wrist-chronometers.”) in 1976 and revised again in 2009. To this very day, this is the framework that the COSC uses to certify wrist watches.

Watch movements are tested for 15 days in the laboratory of COSC, on two different variables, namely:

  • temperature (8 °C, 23 °C and 38 °C).
  • the position of the watch (3 o’clock, 6 o’clock, 9 o’clock, dial on top, dial on the bottom)

A complete summary of the testing procedure can be found on the official COSC website here.

So, why bother with an Observatoire Chronométrique+ certification? Isn’t a chronometer rated Lebois & Co Venturist not enough? Well, you probably have noticed that brands like Rolex, Omega and Grand Seiko for example, started to embrace some stricter standards. Grand Seiko uses an average daily rate of -3 and +5 seconds, Rolex promises -2 and + 2 seconds and Omega uses only positive rates from 0 to +5 seconds. There are probably some more brands that use stricter standards than COSC, but let’s stick to these. Because what’s more, is that these movements are tested after casing. This means that these tests give a better simulation of daily use than just testing the movements only.

That still doesn’t answer the question of why brands should bother in having a more strict test framework than COSC offers. Well, as you know we live in a rapidly changing world. We are surrounded by (consumer) electronics all day, that bring magnetic fields with them. Think of your iPad and protective cover, or the security area at an airport, or your server park (at home or in your company). Magnetism influences the rate of your watch drastically, one of the reasons that certain brands use silicon hairsprings for example. What COSC also does not test, is the water resistance of a watch (as they mainly test uncased movements) and the power reserve of a movement.

Observatoire Chronométrique+ certification

Lebois & Co wants to make a difference in this field. What started out with a dream, and realization with the help of some crowdfunding, turned into a real watch company today. To make a difference in the crowded world of watch brands, founder Tom van Wijlick decided he needed to do something special. The quality of the Lebois & Co watches was already according to his own high standards (as you can read here), he wanted to make sure that an independent laboratory would underline this.

Every Lebois & Co Venturist watch will be tested (and certified) by Timelab. Timelab is a Swiss foundation operating under the authority of the State of Geneva and its experience in watchmaking laboratory dates back to 1886. The renowned laboratory has three activities: the Poinçon de Genève (Geneva Seal) certification, the Observatoire Chronométrique+ certification and a horological laboratory. With their Observatoire Chronométrique+ standard, Timelab has introduced a stringent certification that is open for Swiss made watches. The Venturist will be provided with Timelab’s OC+ standard.

Chronometer and WR

The OC+ certification is based on more thorough and comprehensive testing than the standard ISO 3159(:2009), which allows the watch to receive the title of ‘chronometer’, used and followed by laboratories such as COSC. Instead of only verifying the chronometric performance of uncased movements, the OC+ procedure does so ‘on-the-wrist’ for the fully assembled watch, under various conditions.

The water resistance of the Lebois & Co Venturist is also tested by Timelab. To ensure a watch is (100 meters) water resistant according to the ISO 22810 standard each watch has to withstand 3 different tests: an air overpressure test, a water overpressure test and its water resistance into low depth. For the last test, the Lebois & Co Venturist is placed inside a water tank at a depth of 10 cm for a fixed duration of 60 min. Then, to confirm water resistance, a new condensation test is applied and again no condensation should appear inside the watch to pass the test.

René Peeters (mountaineer and Lebois & Co shareholder)


The magnetism test is performed by applying a magnetic field of 4800 A/m to the watch in 3 different positions. After applying the magnetic field the accuracy is measured to register the impact of the magnetic field. Then the watch is demagnetised and a new measurement is performed. Both measurements have to fall within the criteria specified in the ISO 764 standard.

Last but not least, the Lebois & Co Venturist is tested on its available power reserve. A complete description of all tests performed on the Venturist can be found here, on the website of Timelab.

Every individual Venturist is tested in Geneva for 21 days and is only awarded the ‘Observatoire Chronométrique+’ certificate if all tests are 100% successful.

Lebois & Co Venturist

Now, on to the watch. It isn’t a novelty as such, as it was already introduced to you last October (here). No matter how many certificates are thrown at it, if you don’t like the way it looks, for example, you’re not interested anyway. The good thing is, that the Lebois & Co Venturist looks actually quite nice. It looks like a proper tool watch, perhaps even a bit Explorer-ish, with its large luminous numerals at 12, 3, 6 and 9. It is a highly legible tool watch, with a 41mm diameter and little unnecessary things on the dial. Like a date window, for example (yeey!).

The stainless steel (grade 316L) case is 10.5mm thick and has a beautiful shape, including faceted lugs. The case band has a polished finish, while the top of the lugs and bezel have a satin brush finish. Both sides of the case have a sapphire crystal.

Lebois & Co Venturist


As you can see, the black dial of the Lebois & Co Venturist is very readable. The hour markers are filled with Super-LumiNova (BGW9 grade), as well as the hands. This, for better legibility in low-light conditions. On the dial, you will also find the officially certified chronometer indication as this still remains part of the OC+ certification. ‘Venturist’ is printed in red on the dial, giving it a playful touch. Just as the groove motif on the dial below the hour markers. You immediately notice that Lebois & Co put a lot of thought in the design of this dial, including the length of the hands that reach each of their scales. Unfortunately, this is not always the case with watch brands.


Inside the Lebois & Co Venturist we find the caliber LC-201 movement. This self-winding movement is based on a Sellita caliber and provides the watch with 38 hours of power reserve. This caliber LC-201 movement has Côtes de Genève and perlage decoration and blued screws. All this can be admired through the sapphire case back. Winding and setting of the movement are done via the elegant looking Lebois & Co signed crown.

Lebois & Co Venturist

As you can see, the case back also has all the necessary information engraved in there. The brand & model name, reference number and the fact that it has a chronometer certificate. The case back is screw-in and as written above, the watch is WR to 100 meters (~ 10 bar).

The Venturist comes with a black leather cordovan strap and a (black) NATO strap.

Pricing and Availability

The fact that the Lebois & Co Venturist has been certified with a more strict standard than initially planned, is a big plus. For me, it is also interesting to see that Lebois & Co is not simply a project, but slowly becoming a brand. The Venturist might actually be their gateway to establish this. With the specifications and looks of this watch, there is nothing wrong, it perfectly holds up against some of the more well-known brands out there (and have been for decades).

Lebois & Co’s retail price for the Venturist is €2500,- and for a limited time, this comes with 25 share certificates in the company (representing a value of €1000). These shares in Lebois & Co also allow you to purchase watches in the future with a 40% discount on retail prices (valid for a period of 4 years). More information about becoming a Lebois & Co shareholder can be found here.

Delivery is expected in Q1 2020 and we can’t wait to go hands-on with it.

More information via Lebois & Co online.

Watch specifications

Black dial, Applied hour markers with Super-LumiNova
Case Material
Stainless steel
Case Dimensions
Diameter: 41mm, Thickness: 10.5mm
Sapphire (both sides)
Case Back
Display back, screw-in
Caliber LC-201 (Sellita based), Chronometer certified, Ticking Speed: 28800vph, Power reserve: 38 hours, Jewels: 26, Decorations: Côtes de Genève, Perlage and blued screws
Water Resistance
100 Meters / 10 Bar
Black leather (Cordovan) strap, NATO strap
Special Note(s)
Available in Q1 2020, Observatoire Chronométrique+ certified


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Robert-Jan Broer
About the author

Robert-Jan Broer

Ever since he was a young child, Robert-Jan was drawn to watches, even though it were digital Casio and quartz Swatch models at the time. In the mid-1990s, his interest increased when he started to read about mechanical watches in... read more

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