The purpose of this paper is to analyze L 1 traces in the errors of Japanese EFL learners\u27written English. A total of 178 essays (5978 words) written by Japanese junior college students enrolled in an EFL course were used (91 argumentative essays and 87 narrative essays). Four error types were selected which were identified as influences of L 1 (Japanese), and the distribution of four error types as well as error frequency were analyzed according to the students\u27levels from the beginner to the pre-intermediate levels. The results showed that: 1) the distribution of errors found in the English or L2 essays reflected differences according to students\u27proficiency from the beginner to the pre-intermediate levels and that the choice of essay topic may be a factor; 2) in argumentative essays, errors with the sentence-initial because fragment are prevalent in all proficiency levels; 3) in narrative essays, the error frequency of the anomalous use of the be verb decreases as proficiency increases; and 4) students at the low proficiency level tend to make errors of limited error types repeatedly and did not commit errors of other error types due to their limited knowledge of sentence variations
