Chung is an obvious ideogram, classed under the obsolete radical 丨 kun to pass through. Read chung⁴ it means to middle, i.e. to hit the middle, to attain.

Yung is composed of 庚 kêng to change, as phonetic, with 用 yung to use, as radical, which in turn was composed of 卜 pu to divine and 中 chung the middle. "Get your middle," says one luminary of the 1st cent. A.D., a not unworthy prototype of the famous Mrs. Glasse, "and then you can use it." It originally meant to use; hence the method to be used or followed, a course.