What are the principles of Kanban?

Is Kanban just an extension of just in time manufacturing, or does it have its own principles? Can Kanban be used on its own without JIT, or is it kind of just a different name (or a specific set of rules) for the same thing? I can’t find any type of simple and clear explanation of what the true principles of Kanban are. Is there a list of these principles? Any information that can be provided on this subject would be appreciated.