Since the late 1980s, school curriculum revisions in Japan have sought to promote capabilities and dispositions that transcend subject boundaries and are often labelled 'competencies' in international curricular discourse. This study examines policy documents over the period, showing how Japanese policymakers have sought to navigate pressures internal and external to Japan. It argues that tension between competencies and subject domains in the OECD's PISA surveys enabled both attacks on Japan's so-called "yutori" (relaxed) curriculum revision of 1998-1999, and subsequent responses by Japan's Ministry of Education and Science. Analysis indicates that curriculum reform in Japan has moved from a 'competency-added' revision in 1998-1999 towards a 'competency-integrated' revision in 2017-2018; the latter seeks to resolve the tension between competencies and subject content by developing broader capabilities through distinctive approaches offered by different subjects. Further research is needed to determine how well the curriculum will be translated into school practice.