But they wrote to me : "According to our heritage watchmaking expert, it is the symbol for HPG (High Precision Guarantee) used in the USA for the high frequency calibers (28'800 v/h)." Cheers Christian
Hello Blomman! Fortunately it turned out to be original! I got it confirmed from Jlc heritage department. And also the auction house told me that they know this dial variation as one of their specialists used to own the same watch... But you are right the painting over the date window really seems a
After a lot of research I found out that this dial really existed! I asked at jlc directly and the heritage department told me that the sign on the dial was a styled HPG logo for the American market... All the best from Austria Christian