Feedback during student practice is considered a fundamental component of well-designed computer-assisted instruction (CAI). This research focuses on the appropriate applications of feedback in a CAI lesson which teachers knowledge bases and concepts. The student's learning style/characteristics are a factor in the process. The research follows a 3 × 2 design which includes a pretest, CAI-instruction, posttest, and questionnaire. The factors of the design are feedback (KOR, KOR+sound and line hints, KOR+Explanation) and learner characteristics (field dependent, field independent). The learners, beginner students of Japanese language were assigned to treatment groups via stratified random sampling. Stratification was based on pretest scores of Japanese Grammar Knowledge and leaner characteristics. The result of this research shows that KOR+Explanation type feedback is effective for both field-dependent and field-independent learners.