Origin:

Since the Zhou Dynasty, there has been a saying that "there are three locust trees in front of you, and the three nobles are in the right position", that is, three locust trees are planted outside the palace gate, representing the Taishi, the Grand Master, and the Imperial Palace. The official positions of Taifu and Taibao. The ancients said: "The person who ascends the Sophora Caucasus and the Cauldron is appointed" refers to the position of the Three Dukes. Therefore, in our country's feudal society, people regard the Sophora japonica as the "tree of officials and officials." The planting of locust trees in the Imperial College symbolizes that the college students (college students) can pass the examination for senior officials.

The allusion of "Luoguo Sophora japonica":

Beside the round pool in the west of the "Piyong" Hall of the Imperial College, an ancient Sophora japonica stands tall. Its main trunk is in the shape of a Luoguo, with its upper part facing towards It tilts to the south, and there are traces of the Luoguo tree on the north side of the stem that look like it was chopped with a sharp tool. This is actually because a large branch of the original tree was broken off. People call this locust tree "Luoguo Sophora japonica". There is also an allusion here, because the "Piyong" Hall was built during the Qianlong period of the Qing Dynasty as a place for the emperor to give lectures. The construction was presided over by Liu Yong, a bachelor and Imperial College official. Its "Yongpan River" can be regarded as the essence of ancient Chinese architecture. After Piyong was completed, Liu Yong accompanied Emperor Qianlong and other officials to inspect it. When everyone came to Piyongxi, they immediately saw this obvious ancient locust tree. Because it was said that Liu Yong often presented difficult problems to Qianlong, and it was also said that Liu Yong was a hunchback, Qianlong had an idea and said, "My dear friends, who do you think this Sophora tree looks like?" The officials knew it, but it was difficult to answer. Qianlong also said: "This locust tree, Luo Guo, is not elegant." So he ordered to cut down the Luo Guo locust tree, which was meant to symbolize the death of Liu Yong. Liu Yong cherished the ancient locust tree and said: "Long live, I can't use it. Although this old locust tree is ugly in appearance, it is an ancient locust tree from a long time ago. In the Imperial College, he listened to the classics of saints all day long, and was full of the spirit of Chinese literature and ink. Although it was ugly on the outside, it was ugly on the inside. Show. Now that Piyong is completed, I will always listen to the teachings of the Holy One, and I will be a very loyal minister." After hearing this, Qianlong had no choice but to say: "The Luo Guo loses its elegance. It needs to be cut off and straightened."