Ritter Fretwork?
 

Can anyone shed some light on Ritter's fretwork, please? The process...the idea behind it etc etc.

I did a search but nothing helpful came up.

It's easy to notice that his frets are finished flat (no crown!). This goes against everything I and everyone else I know has ever been taught about fretwork, so why/how is Jens doing it? I don't think he or his instruments would have the status they do if they had playability/intonation issues. I can't figure it out.

Bump.