This paper discusses why and how the Ch'ang-an Buddhist sangha changed their emphasis from the Buddhist concept of emptiness ("k'ung," sun-vata) to that of existence ("yu," being). Founded and led by Kumarajira (344-413)，the sangha advocated using the concept of emptiness to understand the Buddha and his teachings. The sangha, however，started propagating the concept of existence after Kumarajira died. The shift can be traced from some of the key figures in the sangha and their intellectual journeys, and Seng-jui，one the most important disciples of Kumarajira, can be used as an example to illustrate this point. The first section of the article delineates the relationship between Seng-jui and Hui-jui. I argue that Seng-jui and not Hui-jui wrote "Yu-i" (喻疑)，one of most important texts that clearly demonstrates the change in Buddhist philosophical thought in early fifth century China. In the second section，I maintain that Seng-jui's change in thought underwent three stages. At first，Sig-jui added the Saddharma-pundarika sutra (Fa-hua ching 法華經) to the Prajna (Po-je ching 般若經). Later on，he approached these two sutras and their philosophical thoughts separately. In the end，he espoused his new concept，"Saddharma-pundarika for foundation，Prajna for practical application" (Po-je wei yung，Fa-hua wei shih 般若為用，法華為實). By changing his philosophy，Seng-jui left Kumarajira's emphasis on emptiness to develop his own way of understanding the Buddha and his teachings. With his espousing of the concept of existence，Seng-jui's new way of thinking can be used to examine the overall shift in Buddhist philosophical thought during early fifth century China
