This study first delineates the theoretical background of the teaching approach employed. It partly draws on Swain’s ‘Output Hypothesis.’ Although Swain’s original hypothesis includes four features, the approach developed specifically aiming at teaching Japanese learners reduces the features to two. In addition, the use of chunks as discussed, for example, by Widdowson is referred to as well. As a result, Swain’s hypothesis was altered to a modified version with three features: (1) fluency, (2) hypothesis testing, and (3) Widdowson’s idea of chunks which is called ‘approximation’ in this study. The second part of this study explains how a series of experimental lessons are organized and carried out. Then the pre-tests and the post-tests are illustrated. Both pre-tests and post-tests include four different types of questions. The first three are written tests while the last one is an oral interview. The results and the statistical analyses thereof show that the approach is useful in developing certain levels of both writing and speaking skills in the participants