Scrutinizing the inscriptions on the steles preserved in nowadays eastern Gansu, Xi'an and Guyuan is an effective way to identify the characteristics of the development of Tibetan Buddhism in early- to-mid Ming northwest China. In the early to mid 15th century, the Ming court applied rather loose policies to Tibetan Buddhism practitioners, encouraging Buddhist hierarchs like Penden Trashi to promote the spread of Tibetan Buddhism in Beijing and Nanjing as well as reshape the religious landscape of eastern Gansu. Chökyi Gyeltsen, a Buddhist monk from the Jianfu monastery of Xi' an, made full and flexible use of court policies to maximize his benefits on the ground, providing a vivid example of regulatory arbitrage. Examining the competition between two groups of monks from Mt. Xumi over hegemony in historical writing could indicate the power dynamics between royal princes, garrison generals and religious specialists. The loose court policies, flexible use of sect/legal identities by the monks and patronage from local powers constituted a significant catalyst for the fast development of Tibetan Buddhism in early to mid-Ming northwest China.