[2] The prewar Japanese state considered Marxism to be a grave threat to Japan's "national essence" (国体, kokutai).
[1] The Peace Preservation Law, passed in 1925, empowered the Special Higher Police (Tokubetsu Kōtō Keisatsu, abbreviated Tokkō) to persecute communists, socialists, and other leftists by explicitly criminalizing criticism of the system of private property.
[1] In 1927, a sub-bureau, the "Thought Section," was established within the Criminal Affairs Bureau of the Special Higher Police in order to oversee the study and suppression of subversive ideologies.
[2] In the postwar period, whether someone had succumbed to pressure (or torture) and committed tenkō became, among leftists, a sort of ideological litmus test and a form of stigma attached to the careers of left-leaning politicians, artists, and intellectuals active before and after the war.
[2] In the immediate aftermath of the war, many of these leftists attempted to atone for their wartime tenkō by undertaking "self-reflection" (hansei), and often re-embracing Marxism and/or communism with even greater fervor than before.