日本思想家、哲学家鹤见俊辅在战后对“转向”展开了思想史研究。“转向”原为特定的政治术语，指20世纪30年代日本共产党员的思想变节。1945年，《近代文学》的创刊者率先在该杂志上发表批判战时日本共产党员转向的文章，引起新日本文学会与《近代文学》两个阵营对文学者战争责任的争论。同期，鹤见俊辅号召“思想的科学研究会”创办会刊《思想的科学》，继《近代文学》之后继续拷问“转向”，随后又成立转向研究会，以共同研究的方法厘清转向的思想史脉络，归纳战前、战中、战后三个时期转向的不同类型，以传记体裁记录、分析每种转向类型中的典型案例。转向研究会将成果集结为三册《共同研究 转向》，于1959年至1962年间陆续出版。鹤见俊辅研究转向的动机源于其自身经历，他的“转向论”既是对父亲鹤见佑辅两次转向的批判，也包含鹤见俊辅在友人都留重人被质疑为转向者之时对自由主义者转向的思考。鹤见俊辅在“转向论”中贯彻了怀疑主义的逻辑，一方面批判日本共产党对转向的善恶二元论解释，另一方面指出日本社会对转向与非转向的普遍理解简化了两者的关系。于是，他重新定义“转向”的概念为“权力强制下思想的变化”，论述“转向”的要点在于外部权力的强制性与个人思想的自发性，并且该前提下揭示转向与非转向的辩证关系。鹤见俊辅的“转向论”主要将视线聚焦于日本知识分子，他形容明治后期的知识人群体属于“被创造的知识分子”，通过解读知识分子中普遍转向的大多数与大众中坚持非转向的少数者来寻找转向与非转向思想的潜流。其中，战后左翼文学家埴谷雄高作为介于转向与非转向之间的特例，被誉为“形成虚无主义系谱”的伟大转向者。鹤见俊辅借埴谷雄高之例，以怀疑论视角质疑他者的转向观，并在持续关注外部世界的同时不断完善自身的“转向论”，力求在自我与他者的矛盾中进一步探求“转向”之于日本思想史的永恒价值。

Tenkō(conversion), which refers to ideological transformation of Japan Communist Party in the 1930s’ Japan, was taken as an intellectual research subject by Shunsuke Tsurumi, a Japanese thinker and philosopher. After the World War Ⅱ, a magazine Modern Literature has been started, those initial members wrote critical articles to negate the conversion of Japan Communist Party, and it caused a great conflict between New Japan Literature Society and initial members of Modern Literature. At the same time, at the stage of the Institute for the Science of Thought, Shunsuke Tsurumi started a magazine the Science of Thought to continue the research of Tenkō after the discussion stirred up by Modern Literature. He set up a group of Tenkō and tried to use common research to clarify Tenkō issue in an intellectual’s history context. Members from the group divided three periods: prewar, wartime and postwar, determined different types of typical Tenkō and selected representative examples from every type. They wrote these examples in a biography way and analyzed them in historical way. Later, they publish three-volume books The Common Research: Tenkō from 1959 to 1962. The aims of his research is to criticize his father who suffered from Tenkō, as well as to think about liberalists’ Tenkō when Shigeto Tsuru was seen as a public figure of Tenkō. Shunsuke Tsurumi explained and analyzed Tenkō in skeptical logic, to criticize dualism explaination of Tenkō and to make clear of dialectical relation between Tenkō and the inverse of Tenkō. He redefined Tenkō as the change of thinking due to the force of power, and discussed that there are two conditions of Tenkō, the force of power and the spontaneousness of thinking. Furthermore, he focused on Japan’s intellectuals who were born after later Meiji Period, called them as created intellectuals, and compared ordinary people with them to find a developing line of Tenkō. In his study, a leftist author Yutaka Haniya is seen as a special case, Shunsuke Tsurumi appreciated him as a great man suffering from Tenkō for he created a genealogy of nihilism. In the insight of skeplism, Shunsuke Tsurumi expressed his acknowledgement with Yutaka Haniya, observed the contradiction of oneself and others, and tried hard to pursue the eternal value of Tenkō study.