Japanese qigong research became active during the 1990s. In ancient China, qigong was called dao-yin. In the beginning, the techniques of qigong were simpler, and trainees merely stopped their breath during exercise. Now qigong is viewed as a kind of exercise for the health of the mind and body. 'Qi' or 'ki' is an important concept of qigong research and originates from ancient Chinese thought. The original meaning of the word is 'movement of a cloud.' In Japanese language today, the word qi or ki is ordinarily used as an expression of weather change, an activity of the body and soul, and a natural phenomenon. Ki as an ordinary word is often used for something intangible, like ESP when it has paranormal meaning. Today, traditional Oriental medicine like acupuncture is accepted popularly in Japan as a kind of complementary and alternative medicine. In Oriental medicine, qi/ki is used on balance as a practical concept. It is not so important to discuss whether qi/ki has substance or not in a typical c linical environment. However, qi/ki in qigong is used as if it has physical substance. The concept of qigong was defined in China in the 1950s. Qigong is a generic term for various health methods and skills of martial arts, Buddhism, and so on; therefore, the number of kinds of qigong is huge, and it is easy to establish a new qigong method. In the early 20th century, Reijutsu movement occurred in Japan. One of the aims of Reijutsu is to restore health. Reijutsu uses various healing methods, including laying on of hands, direct hand touch, and healing by religious rituals. Reijutsu practitioners visited Manchuria in China and lectured their techniques to Chinese. A qigong performance of emitting external qi is considered to be developed relatively recently and have influences of mesmerism and Reijutsu. In modem Japanese studies, the major effects of external qi can be explained by well-known psychological phenomena (e.g., suggestion). This is the most cautious scenario, and one preferred by skeptics and many scientists outside of qigong research. In contrast, several dozen researchers assume the existence of physical substances of external qi, and they have tried to measure some effects using various sensors of infrared rays and magnetic fields, but detections by sensors were rarely observed and the powers of detected signals too small to cause events directly. However, there were reports on a 'residual' property of external qi that suggest the existence of a substance. Therefore, the concept of external qi is not so simple. In fact, details of the concept of qi or external qi are still obscure. The concept does not apply to all parapsychological phenomena, and there is a difference of training methods between qigong and psi. But, it is very useful to study limited problems at the present time.
