Kuzushi - The State of Perpetually Falling
Contemporary Aikidoka often comes to understand Kuzushi as “Uke bending over or no longer standing straight.” Yet, there are plenty of sports and other athletic endeavors where people change levels while remaining balanced, wherein they bend over while balanced, or even touch the floor while balanced. Meaning, Kuzushi is not satisfied simply because Uke is no longer standing straight. In fact, this is precisely why the contemporary Uke can fulfill his or her choreographed Ukemi - because he/she is yet perfectly in balanced even if he/she is no longer standing straight. Such therefore is not Kuzushi, and any Aikido that purports otherwise an an Aikido that has not solved for Kuzushi.
Instead, Kuzushi should be understood as “a dynamic state wherein Uke’s line of gravity is outside of his/her base of support.” Such an understanding would mean that Kuzushi already has Uke in a falling state, This stands in contrast to a "Kuzushi" that has Uke in balance and preparing for a choreographed fall. When Kuzushi is understood as suggested, this would mean Nage Waza is the aiming of a falling body - not the throwing of a balanced body.