This paper examines the vexed and complex relationship between class, ideology and criticism in 1950s North Korea after the end of the Korean War. Although the KWP presented class as an unitary category, there were in fact many ways of writing about class in these years. Rather than use high-level KWP sources for a single ‘authoritative’ definition of class, this paper examines sources read in the local social worlds of workers. The paper first examines the anxieties created by the implementation of self and group criticism and the measures taken to mollify these worries. It next considers workers’ criticisms of their colleagues published in the Nodongja sinmun. These writings show how class discourse among workers vacated traditional Marxist discourses on class to become more of a cultural category designed to promote self-evaluation and self-reform.