Closed-stance: Toes are pointed towards the side fence.
Open-stance: Toes are pointed more towards the net.
When discussing open stance vs. closed stance, I think back to when I was a junior and we had only one choice. Many players played with continental grips on every shot and only the closed-stance position. With the advent of faster courts, 2-handed backhands, more powerful rackets and less recovery time, the open-stance is much better suited for today's younger players.
If you are more of a senior player, do not give up on your closed-stance or grip. If you are a junior or just starting, I would strongly urge you to consider the open-stance.
There are many advantages to an open-stance, such as:
- Immediate recovery.
- It forces your back hip to turn to into the ball allowing you to hit with your legs.
- It minimizes how far you can take your racket back.
- It is easier to change direction after hitting the ball.
- It is easier to return balls hit near or at you, for example, serves hit into your body.
I teach both stances to my students and allow them to use the one they like the best.
Good luck on the courts!