Jaeger-LeCoultre Caliber 920

The Jaeger-LeCoultre caliber 920 is an automatic ebauche movement that served as the base calibre for some of the most popular watch brands in the industry.

You may see this movement referred to as “JLC 920” for Jaeger-LeCoultre, although technically the company was LeCoultre & Cie at the time, making it a LeCoultre caliber 920 aka LC 920.

This movement was initially produced in the 1960s and 1970s, and is still found in modern watches today.

Interestingly, the 920 was never actually used by Jaeger-LeCoultre.

From Audemars Piguet:

“The watch industry microcosm thrives on rumours. A long-running one holds that LeCoultre Calibre 920 (921 with date) had been developed by Jaeger-LeCoultre for three companies: Audemars Piguet (Refs. 2120 and 2121); Vacheron Constantin (Refs. 1120 and 1121) and Patek Philippe (Refs. 28.255 and 28.255c – numbers referring to the 28 mm diameter and a 2.55 mm thickness without the date, meaning 0.1 mm more than the 2120 version). Yet to this day, there are no documents revealing the terms of a possible contract between the four companies. If the Audemars Piguet archives have not kept a copy, that might be because it was an exclusively verbal agreement.” –Source

Below is a copy of the original tech sheets from LeCoultre & Cie dated 10/2/71, describing the cal. 920 as a “base” and reserved for Vacheron & Constantin and Audemars Piguet (source).

AP Derivatives:

According to Audemars Piguet, AP has had several derivative calibers over the years:

“Derivatives: 2121 (1970), 2120SQ (1973), 2120/2800 (1978), 2120/2801 (circa 1992), 2120/2802 (circa 1995), 2120/2803, 2120/2804, 2120/2808 (circa 2000) and then partially Calibre 5134 (2015).” –Source

Calibre 920 VS 921:

There is a similar caliber 921 with the main difference being that the 921 has a date calendar complication.

Additional Resources:

• Check back for more