In 290 AD, Emperor Wu of Jin, Sima Yan, passed away, and his son Sima Zhong ascended the throne, historically known as Emperor Hui of Jin. This Emperor Hui was a dull and simple-minded person, unable to even understand books, let alone govern the country. When Emperor Wu initially appointed him as crown prince, many ministers opposed it in memorials. Emperor Wu was certainly aware of his son's capabilities and understood that the ministers' advice was for the nation's future, but he did not change his decision. However, he wanted to test Sima Zhong's actual abilities, so he set several questions and sent them to Sima Zhong, demanding answers within three days. From childhood, Sima Zhong only knew how to eat, drink, and play. Due to his low intelligence, even with teachers instructing him in reading, he retained little knowledge, and one by one, the teachers begged Emperor Wu for forgiveness and left. When Emperor Wu's test paper arrived at the crown prince's palace, Sima Zhong was not worried at all; he had no idea what was happening and continued laughing and playing with the palace attendants. This greatly worried the crown princess, Jia Nanfeng. Fearing that Sima Zhong would fail to answer the questions and be deposed as crown prince by Emperor Wu, she summoned several knowledgeable servants from the palace to answer the questions on his behalf. Thus, they narrowly passed this crisis.
After reading the completed exam paper, Sima Yan carefully reviewed it and felt a surge of delight. From the answers, he perceived that the crown prince had meticulous thinking and clear logic, not at all as foolish as others had claimed. At the same time, he felt he had not understood his son well enough and should invest more in nurturing him. With this in mind, Sima Yan sent several memorials from his own desk to the crown prince, instructing him to review and annotate them before returning them for his inspection. The next day, the annotated memorials were neatly placed on Sima Yan's desk. When he opened them, he couldn't help but clap his hands in praise, further solidifying his resolve to let Sima Zhong inherit the throne. In truth, he had no idea that this time, the crown prince's consort, Jia Nanfeng, had once again enlisted help from others; otherwise, the truth would have long been exposed.
Thus, Sima Yan ignored his ministers' opposition and insisted on making Sima Zhong his heir. After Sima Yan's death, Sima Zhong became emperor.
One summer, Emperor Hui of Jin took a large entourage to the Hualin Garden outside the palace. In the garden there was a pond with many frogs. When the emperor reached the pond and heard the frogs croaking, he stopped and asked, "Are these frogs official or private?" The attendants looked at each other in confusion, unable to fathom what the emperor was thinking and thus unsure how to answer. The emperor grew displeased and asked, "Can none of you answer?" The attendants, terrified, fell to their knees with a thud, shouting, "Your Majesty, please calm your anger." Just as the emperor's anger was about to flare, a minor official tremblingly replied, "Frogs on official land are official, and frogs on private land are private."
Upon hearing this, Emperor Hui of Jin found it quite reasonable, his anger dissipated, and he even rewarded the minor official with a generous sum of money. Another year, a famine struck the entire nation, with no grain harvested and countless people dying of starvation. Local officials sent multiple memorials daily to Luoyang, but the court delayed action; during that time, it was common to see the dead lying by the roadside, a truly tragic sight. When Emperor Hui learned of the disaster, he was astonished, unable to understand how anyone could starve to death. He asked his ministers, "Why don't the people eat when they're hungry?" The ministers replied that the crops in the fields had all died, yielding no rice at all. Emperor Hui then asked, "If there's no rice to eat, surely there's always porridge? Don't they know to boil some meat porridge?" The ministers were at a loss whether to laugh or cry; any explanation was futile with such a foolish emperor. Considering the fate of the Jin dynasty rested in the hands of such a ruler, it was no wonder it was doomed to fall.