The Middle Trust: Zheng Shi's Commentary on the Book of Changes

艮游魂中孚云：「豚魚吉，利渉大川，利貞。」孚，信也。兩陰在內，亦以五以中和之氣候之。兩陰猶民，於君在上矣，臣在下候行中正之道，政教信於民，故謂之中孚。

The moving spirit hexagram of Gen is Zhongfu. The hexagram statement says: "Pigs and fish are auspicious, favorable for crossing a great river, favorable for maintaining uprightness." "Fu" means trust. The two yin lines are located within the hexagram, and they are observed using the principle of "wu," the harmonious middle energy. The two yin lines are like the common people, with the ruler above and the minister below. They are observed to see if they can promote the middle and upright path. Government orders and moral education are trusted by the people, hence it is called "Zhongfu."

兩陰者：三辰在亥為豕，爻失正，故變而為小，名言豚；四辰在丑為鱉，鱉魚之微者，爻為正，變以其大，節言魚。三體兊為澤，四值天淵，二五皆坎爻如水，水以水度浸澤所養，故吉。互體是震，震為木，二爻巽為風，木在水上而風行之，濟大川象，君能濟於難也。

The two yin lines refer to the third line, which is in the position of Chen, corresponding to the animal Pig. This line is not in its proper position, so it changes to a smaller term, called "tun." The fourth line is in the position of Chou, corresponding to the animal Tortoise, which is a small fish. This line is in its proper position, so it changes to a larger term, called "yu." The third line's hexagram is Dui, representing a marsh; the fourth line is in the position of the great abyss. The second and fifth lines are both Kan lines, representing water, which moistens the marsh and nurtures all things, hence it is auspicious. The interacting lines form Zhen, representing wood; the second line is in the position of Xun, representing wind. Wood floats on water, and wind moves over it, symbolizing crossing a great river, which illustrates a ruler's ability to overcome difficulties.

【按：以上乃鄭氏《易》義之文，《毛詩·無羊》篇正義亦引此文，惟缺首尾數語。而正義自「浸澤」以下尚有「五亦以水灌淵則魚利，豚魚以喻小民也，而為明君賢臣恩意所供養，故吉」云云，此亦缺而未載，疑脫落也。《稽覽圖》內有此文者，蓋後人以此書專論「卦氣起中孚」之義，故引鄭氏《易》說附入以相闡發，並非《易緯》本文，今退二字附書之。其字之脫誤，則依《詩疏》互為校定雲。】

[Four Treasuries editors note] The above is a passage from Zheng Xuan's commentary on the Book of Changes. The commentary on the poem "Wu Yang" from the Book of Songs by Kong Yingda also cites this passage, but it is missing a few sentences at the beginning and end. Furthermore, the commentary continues from "Jin ze" with "Five, if water flows into the deep abyss, then fish will benefit; young pigs and fish are used to symbolize common people, because they are nourished by the benevolence of a wise ruler and virtuous minister, thus resulting in good fortune," but this part is also missing and not included. It is suspected that some parts have been lost. The reason why this passage appears in the "Ji Lian Tu" is probably because this book specifically discusses the meaning of "the hexagram qi originates from Zhongfu," so later scholars quoted Zheng Xuan's commentary on the Book of Changes and included it in the book to elaborate on each other's ideas. This is not the original text of the Book of Changes' commentary, and it is now written two lines lower as an appendix. As for the missing and erroneous parts in the text, they are checked and corrected based on the commentary on the Book of Songs.