The University of Tokyo only accepts TOEFL scores. Undergraduate, the score submission code is 8404. Generally speaking, TOEFL scores above iBT90 are required. Japanese should be at least one level. You can apply for both IELTS and IBT, and you must pass the level of 1 before you can take the Japanese test in Dongda University, which is the most difficult test in Japan. Of course, the better you study, the better.