The planes are a flat surface on which a straight line joining any two points on it would wholly lie. Image that when your are holding the nunchaku, you are inside a cube. The walls of the cube will be the planes at where you can swing the nunchaku.
Planes:
- Face or Front Plane
- Cross Plane: Between the face and back planes
- Back Plane
- Near Wall
- Core Plane: Between the near and far wall.
- Far Wall
- Roof
- Floor
Here are some pictures, so you will get a better idea:
Face or Front Plane:
Back Plane:
Near Wall:
Far Wall:
Roof:
Floor:
(Based on the work of Kristov: http://www.freestyleforum.net/index.php?topic=4602.0)