In academic history, Hu Yuan, Sun Fu and Shijie were called "Mr. Song's Little Three" by later generations. The three of them were classmates in the sun of Mount Tai. Later, they all accepted apprentices, gave lectures, echoed each other and advocated Confucianism. The thoughts of Cheng Hao and Cheng Yi brothers were directly influenced by it. The Southern Song Dynasty once said, "In 1980, Mr. Anding Hu, Mr. Taishan Sun and Mr. Zhu Laishi started their studies, and then Luo Dunyi (referring to Zhou Dunyi) made a fortune. Therefore, although the Neo-Confucianism of this dynasty was refined in Ilo (Cheng Hao and Cheng Yi), it actually started from Mr. San. Therefore, Huian (Zhu) and Yichuan (Cheng Yi) dare not forget what Mr. San said. " Although the three of them failed to establish a complete theoretical system, their hard practice of "starting labor first" made them pioneers in establishing Neo-Confucianism in the Song Dynasty.

Mr. Hu Yuan, a famous teacher and educator at that time, was most famous for his teaching. Many famous scholars, ruling officials and scholars in the mid-Northern Song Dynasty came from his family. It is said that when he was young, he climbed Mount Tai with Sun Fu and Shijie for many years, and then he studied in Wuzhong. Fan Zhongyan, a reformer in the early Song Dynasty, hired him as a professor in Suzhou and later as a professor in Huzhou. He has thousands of disciples, all of whom are taught by Jing Shu, so that "people in the southeast learn benevolence, righteousness, etiquette and music." In the Qing Dynasty, under the recommendation of Fan Zhongyan, Hu Yuan went to the imperial court to make music, and the official gave lectures to Prince Zhongyun and Tianzhangge, and presided over imperial academy.

Although Hu Yuan, Sun Bin and Shijie studied in Taishan together, and later generations also called them three, it was Sun Bin and Shijie who taught in Taishan for a long time and founded Taishan School. Sun Fuzi Mingfu, a native of Pingyang, Jinzhou (now Linfen, Shanxi), was called Mr. Taishan by scholars because he had given lectures in Taishan. Shijie kept the word "Tao" and named it "Culai". Scholars call him Mr. Zhu Lai, who was born in Fengfu, Yanzhou (now southeast of Tai 'an, Shandong). Shijie was a scholar, and later served as a scholar official in Nanjing. During this period, he met Sun Fu who resigned several times. They feel the same and think the same. Shijie decided to return to his hometown, built a room in Mount Tai and invited Sun Fu to give lectures. From the second year of You Jing (1035) to the second year of Qing Li (1042), Sun Fu has been engaged in the teaching and research of Confucian classics in Taishan, and completed two books, Yi Shuo and Wang Zun Fa Wei in the Spring and Autumn Period. Many people have learned from him, "from Shijie down, they are all apprentices."

"Mr. Song's third grade" has an obvious conservative tendency in politics and is dissatisfied with Wang Anshi's new party. Academically, * * * has more in common: actively joining the WTO, paying attention to the fate of Confucianism, striving to develop Buddhism and Taoism, and attacking the style of study dominated by Ci and Fu since Sui and Tang Dynasties. In view of the flashy style of writing since Sui and Tang Dynasties, Hu Yuan focused on Confucian classics and current affairs in his teaching. In his teaching, he divided Confucian Classics into Confucian Classics and Confucian Classics, and carried out separate education. His efforts influenced the style of study at that time. Sun Bin once said: "The system of the country follows the Sui and Tang Dynasties, and devotes itself to recruiting people with ci and fu. Therefore, people all over the world are committed to the duality of sound and disease, and the pursuit of the Olympics by sages is no exception, rather than being quite unique and not biased towards secular people. Who can take this instead of others? " Like Han Yu, Sun Fu hopes to sort out a Confucian tradition. He believes that after Confucius, Mencius and Xun, Dong Zhongshu played a great role in the revival of Confucianism. However, during the Han and Tang Dynasties, Buddhist elders crossed China, taking death, birth, misfortune and nothingness as retribution. At this time, although many people value the world with literature, only Dong Zhongshu, Yang Xiong, Wang Tong and Han Yu are always upright. Buddhism, old age and Confucianism, driven together, are three things that make people deviate from "benevolence and righteousness" and "rites and music", and the ethics of Confucianism has been destroyed. In view of this, he tried his best to expound Confucian classics such as Chunqiu and Zhouyi to express his desire to restore and maintain the feudal ruling order.

Shijie's criticism of Buddhism, Laozi and the style of writing since Sui and Tang Dynasties became more intense. He wrote three strange essays on China, saying that the disadvantages of Buddhism, Laozi and articles are the biggest enemies that interfere with Confucianism. Consistent with his character of "daring to do things in times of trouble", his criticism of Buddhism and Taoism is also incisive, openly pointing out that the immortals preached by Buddhism and Taoism are as elusive as gold art. He inherited Han Yu's orthodoxy and thought that Yao, Shun, Yu, Tang, Wen, Wu, and Confucius were eternal ways. He praised Mencius, Han Yu and Sun Bin, and pointed out that both Mencius and Han Yu had the merit of protecting Tao, and Sun Bin was another saint after Han Yu.

The lecture "Teacher Song's Grade Three" had a great influence at that time. The place where Sun Fu and Shijie gave lectures was the East Courtyard of Daimiao at the southern foot of Mount Tai. Later, they merged into Daimiao and moved to the western foot of Mount Tai (Wuxian Temple at the western foot of Mount Tai). The school was originally named "Xindaotang" and was renamed "Taishan Academy" in the first year of Kangding (1040).