From what I’ve heard, blitzkrieg was based on Prussian ideas of wars of maneuvering rendered obsolete decades, perhaps centuries ago. And yet, they steamrolled most of Europe, even almost taking Moscow (“almost reaching” wouldn’t be quite so accurate-they got there, but they still lost). The one that confuses me most is that it worked against France, which had a larger army and, IIRC, pre-modern tactics, but still more modern than blitzkrieg. So how did it work so well?
Blitzkrieg as a standalone and "novel" doctrine of warfare remains a contentious topic of discussion amongst historians and military studies. For one thing, the Wehrmacht never actually used the term to describe their form of warfare, and for another the tactic as a whole was not quite as "revolutionary" as Allied sources and postwar writing made it out to be. More can always be said in minutiae (and with greater detail) regarding the development and effectiveness of Blitzkrieg, but for a general overview of the doctrine within the wider topic of the Wehrmacht's early war performance (up until the Battle of Moscow), this thread should be of some help.