Even if you "know" the application to a particular kata movement being able to apply it in a realistic context often seems futile. These drills therefore are the key to unlocking, bridging if you like, (connecting) free movement to the target application. It doesn't matter what style of martial arts you practice (or if you practice no style) the principles inherent in the drills will allow you to eventually transition freely from any point of contact to your technique whether it be a strike, throw, wrench, lock, strangle/choke, etc.
These drills arise from the transitional movements of kata - the consequence of the mandatory requirement to keep your body protected as you move, in addition to the inherent principles of sanchin and tensho kata(s) that are in essence a solution to countering human movement of an adversary while amplifying the effectiveness of one's own movement.
Also available as a DVD in the DVD section of our store.