The concept of "face" is essential to understanding China, Korea, and many other Asian countries. Like "guanxi," "face" is hard to translate, but it basically means your reputation in relation to your community, as determined by dignity, prestige, and social status.
While Westerners don't need to worry too much about their own "face" when visiting China or Korea, understanding the concept can help in business.
Americans and other Westerners tend to ask questions and negotiate directly. East Asians operate more slowly in business, will drag out negotiations, and try to achieve consensus with their peers. When Westerners push for "yes" or "no" answers or criticize, contradict, or otherwise upstage an East Asian business acquaintance, they are likely causing that person a "loss" of "face," which will consequently harm the relationship.
I had more than a few awkward moments in boardrooms with Chinese executives or dealing with public relations representatives where I forcefully pushed for a "yes" or "no" answer that made us both look bad.