This paper examines the dismissals of allegedly Communist teaching staff at Japanese universities between 1948 and 1950 (‘red purge’) as one example of developments usually attributed to a ‘reverse course’ in occupation policy. It argues that the red purge came about less as a result of a change in US policy than through Japanese initiative. Based on primary source material, this paper shows that anti-Communism had been an integral part of the thinking of the Occupation's education administrators since 1946. They were, however, careful not to translate this thinking into victimizing action. Rather, a quantitative analysis indicates that, in bringing about an individual's dismissal, factors such as low academic standing were more decisive than political involvement, implying that the purges were not simply ordered from above. Two case studies of purgees, one a philosophy lecturer from Hirosaki Higher School and the other a professor of anatomy at Kyoto Prefectural School of Medicine, serve to corroborate these findings. Assumptions about a reverse course have led to false conceptions about the respective contribution of US and Japanese administrators to late occupation policies. An accurate assessment of the occupation period requires that historians take into account lower-level events and decisions in order to gauge better Japan's role in shaping occupation policy.