This article updates the trends and developments of Japanese as a second language (JSL) research since Mori and Mori (2011) by reviewing nearly 200 selected empirical studies published in English or Japanese between 2010 and early 2019. The first section of this review examines the cognitive aspects of second language (L2) Japanese development, focusing on vocabulary and kanji (i.e., Chinese characters transferred into Japanese) learning, syntactic development, and the issues surrounding reading and writing. The second part investigates sociocultural issues in L2 Japanese development and use, including pragmatic development, multilingual/translingual perspectives, and multilingual youth. The third section explores the role of affective variables (primarily learner motivation) in L2 Japanese development. The last section considers various pedagogical issues, including corpus-based studies and the development of materials and resources, instructional designs and classroom studies, technology-enhanced language learning and new instructional models, critical approaches to teaching Japanese and content-based instruction. The review of these themes illuminates trends and emerging areas of interest in post-2010 L2 Japanese research inspired by current developments in applied linguistics and second language acquisition (SLA) research, as well as unique features of Japanese language and sociocultural contexts.