"Song" means to contend or litigate. The upper trigram is the Qian trigram, representing heaven. Heaven is yang and has the effect of rising. The lower trigram is the Kan trigram, representing water. Water is yin and flows downward. Their effects are opposite, and the upper and lower trigrams go against each other. On one hand, the Qian trigram uses strength to control what is below, and the Kan trigram uses peril to resist what is above. In terms of imagery, they also oppose each other, thus implying the meaning of "litigation." Simultaneously, the lower trigram represents the "inner self," and the upper trigram represents the "outward appearance." Now, if we assume the inner self is treacherous and the outward appearance is gentle, disputes are less likely to arise. However, in this trigram, the inner trigram is treacherous, and the outer trigram is strong. This means that having a treacherous inner self combined with a strong outward appearance will inevitably lead to conflict, hence the meaning of "litigation." This is the origin of the name "Song" trigram.