Because the meridians serve the whole body from outside in and inside out, they have a dual role. They prevent harmful energies from entering (in the form of bacteria and viruses) the body. They also indicate the presence of harmful energy already inside the body in the form of symptoms on the outside. (See the description of aura later.) These may be felt as aches, pains, heat or cold, and in Shiatsu may be located as areas of particular sensitivity or tenderness.

Any type of "disease" is a sign that the energy within the meridian system is out of balance. When a meridian is blocked, one part of the body is getting too much qi and enters a state of excess, while another part is getting too little and becomes deficient in qi. This will result in one organ becoming overactive while another organ will become underactive and may be fatigued. If you do not correct this problem problem when initially manifested, it can lead to the symptoms getting progressively worse and your disease gets more serious.

Finding these areas is one of the aims of Shiatsu diagnosis and treatment, since their quality and location can tell us a great deal about the origin, location and depth of an imbalance in the entire energy system, which will result in a given disease. The unique nature of the meridians is to reflect this kind of imbalance and then to act as the channel by which the imbalance can be corrected.

Along the meridians you will find more highly charged energy points, which are called pressure points in English or tsubo in Japanese. This is where the qi is most easily affected. Stimulating different tsubo will correct the energy imbalance. In the case of Shiatsu, the affected meridian or points are worked on directly until proper energy flow is restored. By using different shiatsu techniques, such as pressure, stretching, rubbing and corrective exercises, you will be able to release the blockages, "open" the meridian and recharge yourself.