When worse comes to the worst, things and events at their extremes will reverse and turn for the better. Tai (泰) and pi (否), two of the hexagram names in The Book of Changes, represent the positive and negative aspects of things, with one unimpeded and the other blocked, one faced with favorable conditions and the other with adversity, and one good and the other bad. In the view of ancient Chinese, all things cycle around and forever change. When they reach a certain critical point, they will transform into the opposite of their extreme characteristics. The term reveals the dialectical movements of development and change. It gives moral support and hope to people experiencing difficulties, and encourages people to be optimistic, seize the opportunity, work hard, and turn things around. From a dialectical perspective, it represents a sense of preparing for the worst.

The picture of heaven down and earth above is tai hexagram while that of the other way round is pi hexagram. Tai means things are smooth and unimpeded, while pi means things are blocked. Likewise, tai means “open” while pi means “closed.” With one unimpeded and the other blocked, one open and the other closed, the two form a circle. It is a common phenomenon to replace each other regularly, like winter and summer, and day and night, moving on in cycles. Even heaven and earth, as well as sages, cannot escape from changing. (Lin Li: Notes and Commentaries on The Book of Changes)