This tip will deal with low fighting stances—often a neglected and poorly practiced element of fighting and self-defense. Low stances, most often seen in traditional karate and in northern styles of Chinese boxing, are very helpful in self-defense but only if understood and practiced well.
Many top full-contact karate and judo fighters use very low stances. The rule is: The closer the distance the more beneficial is a low stance. Look at the contest performances of technical fighters in those sports and you will notice this.
Low stances are functional but they are not for standing. They are for moving and protecting from attack and counterattack as you move. In this issue you will learn the simplest low stance—moro-ashi dachi (parallel foot stance).
Keep your trunk upright and straight, hips low, supported by flexed legs. Most of your weight is on the front of your feet, both feet pointing in the same direction, one foot advanced about one foot-length ahead of the other.
Learn to move in this position and eventually to strike and kick from it or grapple. In grappling this position makes it difficult for your opponent to “shoot” or do a leg takedown on you. For your attacker’s leg grab to work, you see, he needs you to lean forward (or lose balance in any direction). Moro-ashi dachi keeps your trunk straight while keeping hips low on flexed legs, and this lets you intercept your attacker’s dive for your legs.
In karate-type sparring this position lets you absorb shin kicks to the outside of your legs. Bringing the lead knee to the center, shifting your weight to the back foot, and moving your hips to the back naturally flows you into a cat stance (neko-ashi dachi) which protects you from strikes to the groin and inner thighs.
http://real-self-defense.com/free-self-defense-tips/self-defense-tip-09/