Breguet

Not visible on the breguet tradition 7027 But EVERY tradition 7037 ( automatic seconded retrograde ) has it First I thought it was a manufacturing error…. But since ALL 7037 have this strange notch….. it’s no coincidence not an error But …. Someone knows ...  

...all I can think of is that it facilitates the watchmaker when servicing the movement? Weird...

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... to more conveniently lift out this barrel during service? Marcus

Maybe it's an upgrade from 7027 since 7037 was later.

Confirming with a photo of my 7037 as well. As others have said, I imagine it was placed there to ease the job of the watchmaker. The Naked Watchmaker has a deconstruction of the 7097 (the updated 7037) with lots of photos. Perhaps someone can figure it o...