They are as follows:
Heaven * Unity Earth * Separation
Thunder * Tension Wind * Release
Fire * Movement Water * Rest
Lake * Expansion Mountain * Stability
Each of these four sets has a technical side, as related to the practice of Aikido, and a spiritual side, which relates to our daily life. In reality the four pairs complement each other and cannot exist as separate entities. The spiritual side of Thunder and Wind is health and vitality. The water ki of wind, nurtured deep inside our kidneys, creates our vitality and determines the length of our life.
The next set is that of Fire and Water, the powers of Movement and Rest. The teaching is that Fire moves and water is moved. In other words, it is the mind that moves and the body that is moved. In Aikido practice, the projection of your mind must pass through your partner before physical contact is established. This pure and unrestricted movement of mind is the kototama of Shi and Su.
Water is “rest,” yet this is not stopping. Aikido techniques must always be performed in motion. Water here symbolizes the tightly wound spiral of principle (Ri). It is conformity to this principle that redirects outside force, slowing it down and creating harmonious form. This is Takemusu Aiki.
In Aikido practice the principle of fire and water manifests as Movement before contact and Kuzushi, taking your partner’s balance, upon contact. Unless we receive our partner’s power with rotation there will be a collision of force. The attempt to create form directly has the same result. Force against force kills Aiki.
At this point the spiritual aspects of these two powers should be somewhat clear. Fire is free movement, the creative aspect of mind. When this ki is redirected according to principle and higher reason, harmony and a peaceful environment are the natural result. This is impossible if we are self-serving or shortsighted in our outlook. In the words of Confucius “At seventy years old, I was able to do whatever I wanted and still conform to the way.”