||In recent years, the number of people, both students and adults, learning Japanese has been on the rise throughout the world. With such a fast development, problems and issues concerning both the acquisition of the Japanese language and the teaching method used have become evident. In particular one of the most challenging features of the language has noticeably been detected in the two particles wa and ga. Those two particles, having mainly the function of theme and subject markers, represent an intriguing point for scholars and students alike. Their uses have been at the center of analysis for many years and many linguists have devoted a huge part of their research to inspect their most debated aspects. Researches have focused on different functions each particle can assume and, how their usages can influence the general meaning of a sentence. From Kuno‟s The structure of the Japanese language, considered to be the cornerstone in the field, many different angles of analysis have been used to describe these two particles. Wa and ga are an interesting point of analysis inasmuch as their distinction is vague and subtle both for learners and for Japanese native speakers. Hence, with my research I would like to analyze this issue more in depth, producing evidences of a link between teaching method and particles errors. Through the analysis of written production by L2 Japanese learners, this research confirmed previous findings. It demonstrated a link between classroom instruction and errors in particles usage, calling for much needed reform in Japanese second language teaching.