In some schools, concepts like aiki are described in logical, tangible, terms based on physics, while in other definitions of aiki tend to be vague and open-ended, or more concerned with spiritual aspects.
Many Koreans became virtual slaves for the Japanese during that period. The three upper strokes represent the steam, while the third slanting stroke encloses the character for rice. Most of them are written in the gyosho style, the semi-cursive script of Japanese calligraphy, evoking an image of the life force within the universe and oneself.
Note: This title is often romanized with a dash like this: Aiki-Kai. Titles on older books and signs about Aikido use this form. Two things have become one and are in harmony.
Korean Hanja characters are actually Chinese characters that usually hold the same meaning in both languages.