Wikipedia
Nemawashi (根回し) in Japanese means an informal process of quietly laying the foundation for some proposed change or project, by talking to the people concerned, gathering support and feedback, and so forth. It is considered an important element in any major change, before any formal steps are taken, and successful nemawashi enables changes to be carried out with the consent of all sides.
Nemawashi literally translates as "going around the roots", from 根 (ne, root) and 回す (mawasu, to go around [something]). Its original meaning was literal: digging around the roots of a tree, to prepare it for a transplant. This process involves bringing the dirt from the new location, and introducing it to the tree, before the transplant, so the tree can grow accustomed to the new environment before it gets there.
Nemawashi is often cited as an example of a Japanese word which is difficult to translate effectively, because it is tied so closely to Japanese culture itself, although it is often translated as "laying the groundwork."
In Japan, high-ranking people expect to be let in on new proposals prior to an official meeting. If they find out about something for the first time during the meeting, they will feel that they have been ignored, and they may reject it for that reason alone. Thus, it’s important to approach these people individually before the meeting. This provides an opportunity to introduce the proposal to them and gauge their reaction. This is also a good chance to hear their input. This process is referred to as nemawashi.