How Do Japanese Manage Suppliers

Our customers are Japanese. I learned a lot from them about how to manage suppliers, so I write it out in order to help others.
1, Check the supplier’s manufacturing process. A good manufacturing process can ensure the final quality. They pay much intention to the supplier’s manufacturing process.
2, Check the supplier’s suppliers. They will try to ensure the supplier’s suppliers are qualified.
3, Know the change of important procedures. If the supplier changes the important procedure, the supplier needs to report this to custom.
The following content are the inspection item.