Ki The study of ki is an important component of aikido, and its study defies categorization as either "physical" or "mental" training, as it encompasses both. The kanji for ki normally is written as ?. It was written as ? until the writing reforms after World War 2, and this older form still is seen on occasion. The character for ki is used in everyday Japanese terms, such as "health" (?? genki?), or "shyness" (?? uchiki?). Ki has many meanings, including "ambience", "mind", "mood", and "intention", however, in traditional martial arts it is often used to refer to "life energy". G?z? Shioda's Yoshinkan Aikido, considered one of the "hard styles," largely follows Ueshiba's teachings from before World War II, and surmises that the secret to ki lies in timing and the application of the whole body's strength to a single point. In later years, Ueshiba's application of ki in aikido took on a softer, more gentle feel. This was his Takemusu Aiki and many of his later students teach about ki from this perspective. Koichi Tohei's Ki Society centers almost exclusively around the study of the empirical (albeit subjective) experience of ki with students ranked separately in aikido techniques and ki development.