This data comes from the highest (most recent) caseback and movement numbers that people like YOU and me observe when we visit Lange boutiques and ADs.
I generally make these observations in January each year, and I can always use the help of others.
So next time you visit a boutique or AD, please look at the caseback and movement numbers of any pieces that recently arrived, if you don't mind. It'll give you a good reason to go visit them and to bring a loupe! :)
CRITERIA: We're looking ONLY for caseback numbers greater than 237000 and movement numbers greater than 133000, and we're looking ONLY at working, non-prototype watches that are for sale (because prototype pieces often have much higher numbers than salable pieces, and salable pieces are all that matters for the purpose of this project).
