I mean, the proximate cause of the 1989 protests was the death of the quite reformist general secretary Hu Yaobang. The new general secretary, Zhao Ziyang, was very sympathetic towards the protesters and wanted to negotiate with them, but then he lost a power struggle against Li Peng and Deng Xiaoping (who was in semi retirement but still held onto control of the military). Immediately afterwards, he was removed as general secretary and martial law was declared, leading to the massacre.
I mean, the proximate cause of the 1989 protests was the death of the quite reformist general secretary Hu Yaobang. The new general secretary, Zhao Ziyang, was very sympathetic towards the protesters and wanted to negotiate with them, but then he lost a power struggle against Li Peng and Deng Xiaoping (who was in semi retirement but still held onto control of the military). Immediately afterwards, he was removed as general secretary and martial law was declared, leading to the massacre.