Re: The two body/mind concepts of Japanese Martial Arts.
As not many have vocally said of their experience with Koshi I shall add some for the silent ones.
So far the main points I have stated are these.
1) Koshi is the second, equally important point of mind and body unification.
2) It is the centre of Gravity or Earth Ki.
3) It is in laymans terms the bottom of the back or the back of the pelvis. It is commonly referred to as such in Japan.
4) It is a prominent factor of all Japanese martial arts from their inception.
5) It is commonly held in such martial arts as the power base and also the pivot around which one turns the body in movement.
6) Like hara it can be developed.
7) After prolonged use of weight underside one can become more and more aware of it's significance.
8) Koshi is the key to true relaxation.
Now I will add.
The more aware of it and of the Earth Ki, the grounding Ki, the easier weight underside becomes and indeed the the greater understanding of cutting with a sword.
Also the more one becomes aware of and able to use non-resistance. For the spiritual aspect of Koshi is absolute non-resistance whereas the spiritual aspect of hara is universal love which expands out to kokyu.
Thus resistance breeds bad backs. Thus the bottom of the back is a most usual place to carry stress for the door to Koshi is usually shut tight.
Thus also any Koshi nage I do results in uke falling straight down as if they have fell into a hole. There is no up and over therefore in my Koshinage.
To perform the usual Koshinage I would thus state that in actual fact from the view of Koshi versus Hara or centre then physically you are throwing with the hips but in actual fact you are pushing centre or hara through your back to project the uke over. So I would differenciate here and call that standard Koshinage and show the two ways. That way and my way.
Now when you go to bed tonight in that big soft mattress you can imagine how you're sinking into a place of non-resistance and relaxation. Koshi. Then when you wake up you can yawn and gather the enlvening ebergy of the universe into hara ans see what a great day it's going to be.