Karate has many different stances, each used to create power, flexibility and movement. Some stances focus more on mobility than stability, and vice versa.
Feet together. This is usually a transitional stance, although it is used as the ready stance in some kata. In this stance the knees are bent very slightly. There are no stances where weight rests on a leg with a completely straight knee.
Heels together, toes open at about 45 degrees. This stance is used to perform the formal respectful bow, rei (礼). In this stance the knees are bent very slightly. There are no stances where weight rests on a leg with a completely straight knee.
From musubi-dachi, open heels until both outer edges of feet are parallel. Some styles don't distinguish this stance from heiko-dachi. In this stance the knees are bent very slightly. There are no stances where weight rests on a leg with a completely straight knee.
The feet are shoulder width apart, toes open at 45 degrees. While in hachiji dachi, the karateka is usually in a yoi (ready) position which is a preparatory position that gives a clear starting point for execution of other techniques. The main version of yoi means the arms are slightly moved forward, with fists closed. The fists point slightly to the centre line and are roughly half a shoulder width apart with elbows bent very slightly.
The feet are shoulder width apart, toes facing inwards at 30-45 degrees, knees tense. This stance is used in some formal exercises, for example the tsundome. Also called Chun'be or Naifanchin-dachi. In this stance the knees are bent very slightly. There are no stances where weight rests on a leg with a completely straight knee.
The feet are shoulder width apart, and their outer edges are parallel. This is a common transitional stance in many kata. In this stance the knees are bent very slightly. There are no stances where weight rests on a leg with a completely straight knee.
The feet are shoulder width apart, as in Heiko-dachi, but one foot is forward to where the heel is parallel with the big toe of the back foot. In this stance the knees are bent very slightly. There are no stances where weight rests on a leg with a completely straight knee.
Feet are at the shoulder width. The foot in the front is fully frontal (toes facing forward), the rear foot is turned 90 degrees out, and is positioned in such a way that if the front foot is brought back, its heel will touch the heel of the rear foot. Thus the foot print is shaped like the character レ (or letter L). The weight is kept 70% on the rear foot.