The premise is this: As much as you'd like too, you can't drive your board equally on your toe side as your heal side, you can't. Your body does not bend the same way. Heel side you loose the flex/power of the ankle flex. Your ass drops in a different position, hips and upper body is different. To boot, your front foot is (almost always) pointed somewhat forward, putting your toes 2\" to 3\" further forward relative to your heel from the tail of the board.<br /><br />Based on the theory that the human body and the way it is designed, when you lean forward, all your weight is transfered to your toes. That's why your frontside bottom turn is easier. The opposite is true about your heel-side. That's why you have to squat more and apply more pressure.<br /><br />So in theory, in order to make the board handle the SAME on the heelside turn as it does on a toeside turn, the board would have to be asymmetric in order compensate for our bodies not flexing/powering the same, to be have the same ride. This was the premise used to design the asymmetric race snowboards. As snowboards got narrower, so the degree of asymmetry offset was reduced until it became neglige-able and commercially nonviable in a shrinking market requiring 2x the number of board models (goofy/regular). But the theory remains sound.<br /><br />The theory is, to make a board handle the same on both turns, you need to move the hip and foil back on the heelside, shorten the rail length overall on the heelside, and give it more curve overall. The rail should also be slightly less boxy. The distance between the center fin and the side fin on heelside slightly less than on the toe side.<br /><br />By shortening the heel-side, it relieves the pressure required to engage that rail. Through years of R&D, I have unveiled my first Aysm. model. \"The Einstein\". The thinking mans board. Not only is the outline Aysm, so is the fin placement.