In April 2011, the Ministry of Education in Japan formally introduced Primary School English (PSE) language teaching in Japanese elementary schools. The PSE policy made it mandatory for fourth- and fifth-graders to attend English lessons once a week. Using the theoretical framework on why educational language plans fail [Kaplan, R. B., Baldauf, R. B. Jr., & Kamwangamalu, N. (2011). "Why educational plans sometimes fail." "Current Issues in Language Planning", 12(2), 105-124], language planning and its problems [Baldauf, R. B. Jr., Kaplan, R. B., & Kamwangamalu, N. (2010). "Language planning and its problems." "Current Issues in Language Planning", 11(4), 430-438] and micro language planning [Chua, C. S. K., & Baldauf, R. B. Jr. (2011). "Micro language planning." In E. Hinkel (Ed.), "Handbook of research in second language teaching and learning" (Vol. 2, pp. 936-951). New York, NY: Routledge], this article critically examines the 2011 PSE curricular policy in Japanese elementary schools. Data collection was derived from books, journals, press materials on PSE in Japan and interviews with key stakeholders. The results of the study show that several factors impede the implementation of PSE programme in Japan: lack of curriculum time in learning English, inadequate teaching materials, lack of confidence of teachers to teach English, lack of training and support given to teachers, lack of uniformity in the implementation of PSE programme and an inadequate sociolinguistic environment to sustain the learning of English. This article suggests the need for official language-in-educational planners to adopt a "micro" approach [Chua, C. S. K., & Baldauf, R. B. Jr. (2011). "Micro language planning." In E. Hinkel (Ed.), "Handbook of research in second language teaching and learning" (Vol. 2, pp. 936-951). New York, NY: Routledge] and consider the various challenges faced by the local government, school, and teachers before "rushing" to implement PSE programmes.