Six Harmonies Movement: Co-ordination of the External with Internal Movements
The Six Harmonies are the Three Internal Harmonies (Nei San He) and the Three External Harmonies (Wai San He).
The Three External Harmonies are basically saying that if your body is connected together as a whole (think of a human-body-shaped balloon with the elastic skin connecting everything), when you twist your leg parts (ankle, knee, hip), the twist will be conveyed through the elastic skin of the balloon-body so that the twist also affects the arm parts (shoulder, elbow, ankle) because they are all interconnected by the balloon-skin/qi.
The Three Internal Harmonies are usually written: Xin-Yi, Yi-Qi, Qi-Li. What this means is that if you have a desire to move something or exert a force ("Xin" or "heart" was considered to be the seat of "desire"), that triggers the mind. The mind, in turn, sends the qi to the area where movement/force is needed. The qi is there until the moment the potential force or movement is used and then the qi becomes Li or Jin (strength/force).
We use Chinese terms to convey many of these principles as sometimes the Japanese language doesn't allow for the real descriptions of what they mean.
Xin - Shin - Heart
Yi - I - Intent
Li / Jin - Kei - Strength
Kei, the Japanese reading of the character, tends to mean power, but the original Hanze character means internal strength. If we breakdown the meanings of the character it means strength on the right and fascia, or connective tissues on the left hand side. In Japanese the word looses the connective tissue part of the character.
勁 - Chinese Hanze
力- Japanese Kanji
Why do we consider this important?
Aikido without 6 Harmonies Movement is simply an external facsimile, or copy, of what it is supposed to be. The founder of Aikido trained in this movement system. In our minds, Aikido without 6 Harmonies Movement, or, internal movement as Ikeda sensei would say, is empty practice and therefore not Aikido.