The process of determining which actual pattern is on hand is called (, usually translated as "pattern diagnosis", "pattern identification" or "pattern discrimination"). Generally, the first and most important step in pattern diagnosis is an evaluation of the present signs and symptoms on the basis of the "Eight Principles" (). These eight principles refer to four pairs of fundamental qualities of a disease: exterior/interior, heat/cold, vacuity/repletion, and yin/yang. Out of these, heat/cold and vacuity/repletion have the biggest clinical importance. The yin/yang quality, on the other side, has the smallest importance and is somewhat seen aside from the other three pairs, since it merely presents a general and vague conclusion regarding what other qualities are found. In detail, the Eight Principles refer to the following: