A method where a process signals its predecessor that more material is needed. The pull system produces only the required material after the subsequent operation signals a need for it. This process is necessary to reduce overproduction.
I too have heard of Kanban and JIT from my fellow arrogant valley douches. I would like to understand the specific manufacturing processes that make one-off products of production quality viable.
I suggest to read Gemba Kaizen books. Yes, it is hard to understand first, but then you realize that Toyota Way is like 3D printer — add only what is needed right now, do it fast, be precise.
So yes, you are right — Toyota Way is not viable for mass production, but it perfect for areas where human labor is still plays major role in manufacturing, e.g. programming.