After his expulsion, Soedjatmoko moved to Surakarta and studied Western history and political literature, which led to an interest in socialism. Some figure that affected him besides Karl Marx were Ortega y Gasset and Jan Romein. While in Surakarta he also worked at his father's hospital. After Indonesia proclaimed its independence, Soedjatmoko was asked to become Deputy Head of the Foreign Press Department in the Ministry of Information. In 1946, at the request of Prime Minister Sjahrir, he and two friends established a Dutch-language weekly, "Het Inzicht" ("Inside"), as a counter to the Dutch-sponsored "Het Uίtzicht" ("Outlook"). The next year, they launched a socialist-oriented journal, "Siasat" ("Tactics"), which was published weekly. During this period Soedjatmoko dropped the name Mangoendiningrat, as it reminded him of the feudal aspects of Indonesian culture.