'kingpin' means the leader, usually the leader of a criminal organization.
I think that the name comes from bowling, where the first pin is the most important.
Sorry I am not posting photos lately; there's something wrong with my camera.
This blog is mainly to explain a different English language expression every day. Sometimes I post other stuff. I also have a YouTube channel which is mostly about computer software: https://www.youtube.com/englishspacedog
