Alexander Sensei: "Saito Sensei gave this set of three pictures to several of his deshi to illustrate the difference between the Aikido sword stance and a conventional straight stance used in sports Kendo and some other martial arts.
In the straight stance the hips face into the line of attack, whereas in the Aikido stance the hips are rotated back away from the line of attack.
If two people using the straight stance attack each other from above simultaneously, they will hit each other. However, if one person is in the Aikido stance, he will hit the other person, but the other person will not hit him."