From 1960 until 1965, the People's Republic of China (PRC) built a remarkably cordial quasi alliance with the Republic of Indonesia. At the same time, however, the years between 1960 and 1965 were marked by two large waves of anti-Chinese movements in Indonesia. Although more than half a century has passed since these events, our understanding of Chinese foreign policy towards Indonesia during these turbulent years remains incomplete. In 2008, the Chinese Foreign Ministry Archives declassified for the first time documents produced during the years between 1961 and 1965. However, very recently in summer 2013, the Chinese Foreign Ministry Archives re-classified the main body of its collection. Through examining this body of fresh but currently inaccessible official records, this article aims to bridge the gap between scholarly works on the PRC's diplomatic history and overseas Chinese history. By tracing the processes by which Chinese diplomats dealt with Sukarno, the ethnic Chinese in Indonesia, and the Communist Party of Indonesia (Partai Komunis Indonesia, or the PKI), this article argues that the ambivalent Chinese alliance with Indonesia was shaped by three disparate pressures which interacted and competed with one another: the strategic need to befriend Third World countries, ethnic ties to the Chinese in Indonesia and ideological commitment to the international communist movement.