The origins of zen shiatsu is in Oriental medicine, but it was adapted to the Japanese environment.

All types of shiatsu stimulate blood circulation directly, like western style massage such as Swedish. In doing so, both of these systems help release poorly flowing blood in the skin and muscles, and hence help ease tension and stiffness that arise from that congestion.

But there are important differences, both in the way shiatsu is practised, and its other effects. Unlike western style massages, shiatsu uses the meridian system, which can be pictured as like the arteries of our physically embodied energetic system. Consequently, the effects of shiatsu go much deeper, and can help the organs themselves, our autonomic nervous system, and our hormones, as well as our joints, tendons and muscles.

There are actually at least 6 different styles of shiatsu practised in the West today, though some practitioners combine the different approaches in one treatment session. Zen shiatsu was developed by Shizuto Masunaga, and came out of a time in Japan when the most popular style of shiatsu, taught by Namikoshi's schools, had a strong alignment with western medicine. Masunaga sought to bring back the traditional Oriental medical approach and philosophy, as well as maintaining the advances in physiology that had been developed in the West.

In developing zen shiatsu, Masunaga facilitated a more complete understanding of the meridian system. He taught how to use the meridians to balance a person's psychological and physical systems so that the body was in a greater position to heal itself.

Zen shiatsu is generally less painful than Namikoshi's style, in the hands of a skilled practitioner. The reason is that both hands are kept on the body, and the object is to find the most 'kyo' and most 'jitsu' meridians, and work on these together. Kyo refers to an 'empty' meridian - that is, one with the least amount of energy. And jitsu in this context means a meridian with an excessive amount of energy. So, by working on the two together, the body achieves a state of balance.

When a zen shiatsu practitioner is diagnosing for kyo and jitsu, the awareness is on the relationship of meridians to each other. They define each other. If a person's body was in a complete state of balance, there would be no kyo or jitsu. But if one meridian becomes kyo or jitsu, it causes an imbalance in another. So the key is to assess the meridians in relation to each other to find the 'match', that when treated, will balance out.

Shiatsu can be practised at home, on oneself, on family and friends. But a professional shiatsu involves the practitioner having both a good grasp of treatment and diagnosis. Diagnosis, in shiatsu and Oriental medicine, is quite different to the western medical approach. Shiatsu takes a very individualized approach - it doesn't look for a disease with a set criteria of symptoms. Rather, it assesses the energetic and physical balance - or imbalance- within the conditions the individual is presenting, and treats accordingly. So even though two people may come in with headaches, the treatment, the choice of meridians, the combination of stretches, would be different.

Shiatsu is very effective at preventing disease by addressing imbalances before they manifest as illnesses. Another difference between it and a western approach, is the integration of the responsibility of the individual to maintain their own health, through choices that support their own health. These choices may be dietary, lifestyle, or more fundamental choices about the direction their life is taking.

References:
1. Chris Jarmey and Gabriel Mojay, Shiatsu
2. Shizuto Masunaga and Wataru Ohashi, Zen Shiatsu