The meaning of this hexagram in which an excess of yin lines prevails, may be grasped by contrasting its image with that of hexagram number twenty-eight, Critical Mass, in which an excess of yang lines prevails. Here the idea is the prevalence of small or inferior powers, and the lesson to be learned is how to distinguish essentials from non-essentials. Is it ever good to deviate from the established course of procedure? The answer is that it is permissible only in small matters, but never in matters of import. Sometimes form may be dispensed with, but never substance, and the thing must always be done responsibly and with appropriate humility. The symbol of the bird is to teach humility -- it is better for it to descend, keeping near to where it can perch and rest, than to ascend into the homeless regions of the upper air.