Aikido Intro #5: Hanmi
"The founder said that the key to effective hip work was in the legs...this means the hips cannot be stable unless the legs are steady. That is why I insist my students keep their back foot in line with the front foot when in hanmi. It is incorrect to move the back foot off that line...When you turn quickly to the rear keeping your front foot on the line, you should be able to recover your hanmi stance. But if your feet are not in line you will not be able to assume hanmi smoothly after turning 180 degrees without correcting the rear foot position. You will lose control and the motion will slow down. If the limbs are moved in the wrong order, you no longer have an effective technique. If you cannot do correct footwork, you will not be able to use your hips effectively."
-Shihan Morihiro Saito
Fr. 1991 interview Aiki News #88