Sosan, also known as Sengcan, was a Chinese Zen teacher and the Third Zen Patriarch. He is known for his teachings on the practice of meditation and the concept of emptiness. Sosan is said to have been a student of the Second Zen Patriarch, Huike, and was also influenced by the teachings of the First Zen Patriarch, Bodhidharma.

According to historical records, Sosan was a student of Huike, who was a disciple of Bodhidharma. Huike is known for his famous encounter with Bodhidharma, where he cut off his own arm to show his determination to become Bodhidharma's disciple. After Huike became the Second Zen Patriarch, Sosan is said to have studied under him and learned the principles of Zen meditation and the concept of emptiness.

Sosan's teachings also show a strong influence from Bodhidharma, the First Zen Patriarch. Bodhidharma is credited with bringing Zen Buddhism from India to China and is considered the founder of Zen in China. His teachings emphasized the practice of meditation and the realization of one's true nature, which are also central themes in Sosan's teachings.

In addition to being a student of Huike and being influenced by Bodhidharma, Sosan also studied under other Zen masters. It is said that he received teachings from the Fourth Zen Patriarch, Daoxin, and the Fifth Zen Patriarch, Hongren. These two masters were also disciples of Bodhidharma and played important roles in the development of Zen in China.

Sosan's teachings and writings also show a deep understanding of the teachings of the Diamond Sutra, one of the most important texts in Mahayana Buddhism. This suggests that he may have also studied under other Mahayana teachers.

In conclusion, Sosan was a student of Huike and was influenced by the teachings of Bodhidharma. He also studied under other Zen masters and may have received teachings from Mahayana teachers. Sosan's diverse influences and teachings demonstrate the interconnectedness of Zen and Mahayana Buddhism and highlight the importance of lineage and transmission in the Zen tradition.