ABSTRACT Insufficient scholarly attention has been given to how UN human rights treaty bodies can induce states to implement concluding observations (COBs). This is because previous studies tend to underestimate the treaty bodies as weak, and instead focus on domestic factors. A case study of the Japanese implementation of treaty bodies’ COBs, however, reveals that domestic mobilization does not always succeed in changing government policies because of Japanese authorities’ inadequate understanding of international human rights law in areas such as gender equality and the prohibition of hate speech. Exploring treaty bodies’ role in inducing such states’ implementation of COBs is therefore crucial. To tackle this, this paper applies the theory of Goodman and Jinks, and reveals that the treaty bodies’ design is aimed primarily at persuading rather than acculturating states. If acculturation is incorporated into their design, it follows that treaty bodies should coordinate with the Human Rights Council, and that the Human Rights Council should follow up COBs in the Universal Periodic Review (UPR). Because ‘enforcement’ of COBs by the UPR could undermine treaty bodies’ work, this paper suggests a modest solution: that the UPR should cover the concerns expressed in COBs.