So generally speaking, kuzushi means to off-balance your opponent. On Saturday just gone, we were practising body throws, the kind you might see executed by a judo player. As with everything in TSYR, things are a bit more subtle than you first expect. You are not just hauling someone over your shoulder or hip. In the first instance we are supposed to make kuzushi. That is, take our opponent's balance from them. However, we are then supposed to keep kuzushi through the whole movement, at no time is uchitachi supposed to regain their base. This is very hard to achieve. We all struggled to keep a constant feeling of kuzushi through the whole movement. One way to think about the throw is to think of a spooling motion whereby uchitachi is drawn into uncontrollable forward momentum by shitachi's movement. The result being an easy throw to the mat. We are fortunate to have many different body types in our dojo. I am tall and light - very easy to throw, and at the opposite end of the spectrum we have a guy who is short and heavy - like trying to throw a small boulder. In an ideal world with perfect technique we can be thrown with equal ease. It is not an ideal world.
If we look deeper into kuzushi we see that breaking someone's balance becomes an intricate art. In which way do we want uchitachi's balance broken? If I create kuzushi so that he is falling away from me, the throws I mentioned above would not work. They require uchitachi to be falling forward. Kuzushi 'sets up' a technique so the next step is ensuring I create useful kuzushi. I'm sure there is even more to this but I'm still figuring it out. I'll get back to you in 10 or 20 years.