Centre Power
"Chu Shin Ryoku", the 'centre power', refers to the strength required to maintain your body's centre line straight. If you don't develop this you cannot achieve "Shu Chu Ryoku", Concentrated Power or "Kokyu Ryoku", Breath Power.
If you don't develop 'centre power' you are just going through the motions of Aikido techniques without achieving true power. If you want strong 'centre power' you have to be able to develop correct "Kamae", Posture. You can feel your 'centre power' when you practice correct Kamae. So, at the same time as you practice Kamae, you learn how to strengthen your 'centre power'.
It is not easy to develop strong 'centre power’; it depends on how much you try. The key lies in the big toe of the back foot. The power comes up from the big toe of the back foot and is transmitted into the hips and the lower back. You have to develop strong big toes through practicing "suwari waza", kneeling techniques. You have to develop strong hips through practicing "Kihon Dosa", the basic movements. The techniques of Yoshinkan Aikido are those achieved by training yourself and making yourself correct.
The essence of Aikido is "Kokyu Ryoku", Breath Power. It is not important to beat your opponent by throwing or holding them if it makes them feel hateful. Aikido is only Aikido in a true sense when your opponent doesn't have any bad feelings towards you. When this is achieved you are really winning. It is the real goal of the practice to strengthen your 'centre power'.
"The Yoshinkan "House for Cultivating the Spirit"