Derek is demonstrating the precise angles of the left neutral stance . Notice the difference of the angle of left and right foot, the left is at 45 degrees , the right at 35, This ensures freedom to release the hip into the strike
- Another look at the foot angles. These are also the same for a right neutral where the feet are reversed in the opposite position, and interestingly, a front stance where the opponent would be located on the white line as opposed to perpendicular to it.
Source:
http://bmsmartialart.com/253