American managers believed that once a production system achieved stability, it should be maintained at that point. Japanese managers, on the other hand, believed that production stability was just a starting point, and from that point onward, the continual improvement must be applied.
The Japanese also believed in a harmonious relationship between managers and workers. That too was contrary to Detroit’s historic adversarial relationship between management and labor. Japanese managers actively encouraged all workers to suggest ways to improve processes. Detroit’s managers adamantly prohibited workers from suggesting changes.
It is also a process that, when done correctly, humanizes the workplace, eliminates overly hard work (muri), and teaches people how to perform experiments on their work using the scientific method and how to learn to spot and eliminate waste in business processes.
One point I would make, is that Japanese manufacturers focused on “continuous improvement” (Kaizen):
https://www.chegg.com/homework-help/questions-and-answers/american-automakers-finally-caught-japanese-terms-product-quality-35-years-us-auto-industr-q55211533
Edit: A better source on the Kaizen method
https://en.wikipedia.org/wiki/Kaizen