La Joux-Perret Caliber LJP-G101

The La Joux-Perret caliber LJP-G101 is a Swiss made automatic 3-hander, true no-date movement with 24 jewels, beating at 28,800 vph.

For a more complete breakdown of this movement, check the G100 caliber listing.

Caliber G101 VS G100:

The G101 is the no-date version of the G100. In the G101, the calendar complication is completely removed, allowing for a 3-hand watch design without a phantom date position when setting the time. If you see 3-hander watches advertising a G100 movement inside, it’s either because they do not fully understand that they have a G101, or they are simply using a G100 with an undesirable phantom date position.

Unfortunately, it does not appear that real-life examples of the G100 or G101 have caliber numbers marked on the rotor or under the balance wheel. If you come across one of these movements with a caliber number, please comment below.

Tungten Rotor:

The G100 rotor is ball-bearing style with 3 screws holding it in place (similar to the Miyota 9 series). It is made from solid tungsten. Tungsten is the heaviest naturally occurring metal (source), which is likely where the 3 screw design comes into play.

Here is what Furlan Marri says this about the rotor in their G101 powered watches:

“… a full tungsten rotor with palladium coating ensures smooth rotation and weight distribution.” –source

Miyota 9039 Clone?

The G100 caliber listing goes into more depth about it being a clone or not, but for the sake of covering the no-date G101, it can be compared to the Miyota 9039 framework.

Some similarities between the 9039 and G101 are:

• Both have a jewel count of 24.
• Both have a beat rate of 28,800 vph.
• Both have the same 3 screw ball-bearing rotor design.
• Both appear to have a very similar architecture overall.

If you look closely, it really looks like LJP took the 9039 (Miyota Series 9 in general) and reworked the CAD design to allow for curves where the Miyota is straight, and other finishing techniques such as chamfered edges. Is it a unique design from scratch? Certainly not.

Differences include:

• Miyota using Citizen’s Paraflex anti-shock and the G101 using the Swiss made KIF device.
• The G101 has a screw style fine tuning device on the regulator, the 9039 does not.
• The 9039 has a power reserve of 42 hours, the G101 offers 68 hours of running time.
• Accuracy of the Miyota 9039 averages at -10 to +30 seconds per day compared to the lowest grade of G101 at +/-12 sec/day (see below).

Grades of G100:

Similar to how ETA and Sellita offer different grades of movement based on finish, testing and accuracy, MLJP also offers multiple grades. When contrasting low and high grade options, the G100 is available in Standard grade or Soigne. Soigne is the label given to their highest grade.

Accuracy Rating:

Using the aforementioned grades to compare accuracy, MLJP claims that the accuracy of the G101 Standard version is tested in 3 positions with timekeeping averaging out to +/-12 seconds per day with a maximum deviation of 30 seconds per day. The higher grade version is tested in 4 positions and times out to an average of +/-7 seconds per day with a max deviation of 20 sec/day.

Replacement Prices:

At the time of this post, Caliber Corner was unable to find USA based watch parts suppliers with the G101 for sale, therefore a confirmed retail price is unavailable. There is a Switzerland based seller on eBay with a new G101 for sale priced at $295 USD. If this is any indication of actual pricing from the manufacturer, then it is not priced competitively against the SW200-1, although it may be worth it for your project if you desire the ability to offer a longer power reserve.

Video:

About Manufacture la Joux-Perret:

MJLP is based in La Chaux-de-Fonds, Switzerland. It is owned by Citizen Watch Group (Japan) as of April 2012 via acquisition of Prothor Holding SA.

Pros & Cons:

Pros:

• Shares dimensions with popular movements
• Decent power reserve
• True no-date with calendar system completely removed

Cons:

• Parts may not be easy to source
• Tech sheets and drawings not readily available
• Has not been on the market long enough for the community to share experiences with performance or serviceability

Caliber Confusion:

Both of the brands featured in the known models section of the specs chart above seem to be plagued by what Caliber Corner refers to as caliber confusion.

anOrdain has a 3-hander without a date, described as a caliber G100 on their product pages and social media.

anOrdain was among the first brands to use a movement from La Joux-Perret in their watches, so one might think the caliber confusion comes from being an early adopter and perhaps JLP either did not have an official designation for the no-date variant of the G100, or only had the G100 available at the time and anOrdain’s Model 1 has a phantom date mode or they made modifications to the base movement themselves – such as removing the calendar components.

But as of the writing of this post, Furlan Marri introduced their Sector series of automatic watches on 3/23/23. It is a three hand, no-date watch that their official product description quotes as being a caliber G100:

Editor’s Comment: Nothing against these brands, but if you are a longtime reader of Caliber Corner, you know it’s a pet peeve when watch brands do not even know what caliber they are using – and watch blogs and other journalists write (paid?) marketing fluff pieces without confirming the caliber in the watch.

Additional Resources:

• La Joux-Perret official site
• List of La Joux-Perret calibers