In an earlier time in China, a doctor wasn't paid to give treatment to sick people but to keep a person healthy. As soon as a person became ill, he got his treatment for free. Health care was basically preventive. There were several types of treatment: acupuncture; medicines and herbs; diet; moxibustion; tui na and anma (theraputic massage); and special exercises such as tai chi chuan. The Japanese borrowed many things from Chinese culture to use and develop, combining traditional Chinese medicine with Japanese techniques to develop shiatsu.
Shiatsu literally means finger-pressure. Natural body weight is used when pressure is applied on special points on the body. Through this pressure the energy flowing in the meridians is influenced. This energy is called chi.
Chi by itself is invisible, but the way chi works can be seen in the body. When a wound is healing "just by itself" it is the work of chi. Traditionally, everything was seen as an expression of chi. Chi is the origin, the power of life. When chi stagnates, the body becomes ill.
Meridians are the energy channels of chi. They don't correspond with any part of the body recognized by Western medicine. Think of them as regulating the flow of energy in the body. Each meridian is related to one of the five elements of the universe: wood; fire; earth; metal; and water, and is connected to one of the major organs of our bodies. Along these meridians are pressure points that act as gateways. These gateways are what Shiatsu acts upon.
Diagnosis & Treatment
In Oriental medicine there are several ways to make a diagnosis, these are:
Setsu-shin is the most important one. Reflection zones on the head and back, tongue, and body along with the pulse and manipulations of the joints are used by the therapist for diagnosis. During a massage the therapist gets information which he uses for diagnosis. The diagnosis will change in time because the chi is changing as the therapist works on the body. The information the therapist gets, can then be used immediately for treatment. This is the major difference in acupuncture and shiatsu as opposed to Western medicine.
Another important difference with shiatsu is physical contact. The patient experiences deep and intense support. If they feel safe enough they will experience problems that are normally hidden. This is very important, because behind every "pain" that asks to be cured, there is another "pain" that's hidden. Giving attention to these underlying problems leads to the beginning of recovery.
If you want to learn more about Shiatsu read Shiatsu: Therapeutic Art of Japan by Hazel Chung.