This presentation outlines an in-service training workshop for high-school teachers of English as a Foreign Language, accredited by the Japanese ministry of education. The workshop focused on the use of authentic materials to motivate students and attempted to gauge the participants’ existing ideas about authenticity in language teaching and examine how these fit with the way English is currently employed for international communication in the global context. I proposed during the workshop that authenticity be reconceptualised as a continuum, incorporating contextual and social dimensions. Participants were then asked to reflect on their concept of authenticity before and after the workshop to examine the impact of the proposed continuum. Data were collected from participants in the form of a written reaction to the workshop and questionnaire, as well as teacher/researchers’ observations and journal entries. Most of the data are qualitative, and the study design was based on exploratory practice, so data came from pedagogic sources from the workshop. The research attempted to involve all the participants in a way that encouraged them to reflect on their own practice. Although at times I present data in a way which quantifies the responses, the majority of data analysis was done in an interpretive way, coding the data as I went through it and then re-coding it as the bigger picture emerged. I used NVivo analysis software to create nodes and run word frequency queries as I worked through the data, which helped in selecting the major themes for the responses. From a total of 33 participants, 23 (almost 70 per cent) had culturally embedded definitions of authenticity, with 18 participants (over 50 per cent) specifically making reference to native speakers. Participants commented that the workshop had helped them to expand their ideas about authenticity, which for many was a motivating or empowering experience.