In his essay Far-Reaching Concerns (远虑), the Song writer Su Xun divided the ways of the sage ruler into three. The constant principles may be known by all the people. Expedient measures are not for the people, but the ministers may know them. Secret plans are not for the ministers either. Only the “ministers of heart and belly” (腹心之臣) may know them.
The sage, Su Xun wrote, honors such a minister “like a father and teacher” and loves him “like a brother.” They hold hands, enter the bedchamber, and share daily life, sleep and meals. Between them, “nothing known goes unsaid, and nothing said is held back” (知无不言，言无不尽). Only then can they discuss the secret plans of the realm.