Both sides grapple in right natural posture. Tori advances with the left foot, then the right foot, while pushing Uke back. Uke responds by stepping back with his right foot, then his left foot, and begins to step back with his right foot again.
At the moment Uke begins to step forward with his right foot, Tori steps his right foot in fron of Ukes right foot, thereby shortening the distance between them, and then steps his left foot round behind his own right foot, and opens his body to the left to take a right han-mi posture. He lifts and pulls with the right hand, pulls with the left hand lifting the elbow up, and, pulling him open to the left side, he lifts Uke to the right front corner and breaks his balance. Uke is not able to transfer his weight onto his right foot, and rises onto the tips of his feet as his balance breaks.
At that moment, Tori supports his body weight on the left leg and, straightening his right leg up in front of Uke, puts the back of his ankle diagonally across the area below Ukes right knee, ths restricting the free movement of his leg. While twisting his body to the left, he lifts and pulls further with the right hand, pulls diagonally downwards with the left hand, and throws Uke around the fulcrum of his right leg. Uke is unable to step his right leg forward because his knee is restricted, and he twists forward as he is thrown in rotating a motion.
The concept of this technique is almost the same as that of hiza-guruma. In hiza-guruma, Tori throws Uke with the sole of his left foot on Ukes right knee, but in ashi-guruma he throws Uke with the lower end of his right leg on Ukes knee. It is a good idea to remember the concepts in comparison.
At the moment Uke steps back and transfers his body weight, Tori steps in, thereby closing the distance between them, takes a right han-mi posture, lifts Uke, and breaks his balance using body control. It is important to seize the opportunity to position (tsukuri) at the right moment with exact timing. If Tori is slow, Uke will transfer his weight onto the right foot, and Tori will not be able to lift him and break his balance. On the other hand, if he is too fast, Uke will respond by stepping forward with his right foot in a stable posture.
In short, Tori should position Uke (tsukuri) by restricting the free movement of his right leg, so that he is unable to step forward and his upper body only is pulled forward.
The back of Toris right ankle should touch the lower part of Ukes right knee, and their waists should remain seperate.
Tori should aim to stop Ukes right leg moving forward by pressing with his right foot. It is not possible to sweep up with the right leg because their bodies are seperate, therefore Tori must use a pressing action instead.
When Tori throws Uke around the fulcrum of his right leg, it will not be effective if he relies on the power from his arms, even if he twists around. Tori must lift Uke from a straight and inflexible posture, break his balance, then use his right foot to press on Ukes knee, push with the right hand, pull with the left hand, and synchronizing these movements, turn and twists to throw Uke down.
Toris body control (tai-sabaki)
Tori positions Uke for the throw (tsukuri), and at the moment Uke steps forward with his left foot, Tori steps his left foot to the tip of Ukes left foot while lifting Uke straight forward to break his balance. THen, piovoting on his left foot, he swings the right leg up in front, and rotating the body in a large motion, presses Ukes right kneecap down with the right foot.
In this situation, Tori adapts and continues from Ukes technique. Uke executes a right o-soto-gari, or a right tai-otoshi, and at the moment it does not prove effective, Uke brings his right foot back and returns to stable posture. At that moment, Tori lifts Uke with both hands, breaking his balance, presses his right foot onto Ukes knee, driving it back, and continues to execute ashi-guruma.