Psychotherapy is based upon the understanding of client and the communication between therapist and client. Understanding of client means therapist understands client. But it is more than that. Understanding other includes not only understanding client's thinkings, feelings and his (her) personality, but also includes understanding all the phenomenons which occur in the therapy room. It is as if a boundary of the client expands to the entire room. In such cases, therapist himself is at once the subject who understands and the object who is understood. Moreover,therapist tries to understand parent-child relationships and other interpersonal relations, the societies, climate and nature which circumvent the client. And after all,therapist understands the context or the constellation which break the surface of them. Therefore, such understanding works with a special type of communication. This type of communication is at one time a way of communicating meanings, at the other time an exchange of stimuli which influence each other, or a field where battles of thoughts develop, or a way of encouraging or protecting the client. It is a communication as interaction where a sense of reliance ocurrs. That is why therapist's understanding of client goes side by side with client's understanding of therapist. At the symposium, I will try to discuss these matters thoroughly.