Starting A Wing-arc (Bong Sau) Turn (Chu Shong Tin Training Episodes

As a cross reference, you can also read the post [Rotation in Joints (Separate but at the Same Time) - Composing Movements] 2013.12.12 at / ideaswingchun .
Note: The three methods demonstrated in the footage are contrastive. They might altogether be regarded as a rough portrait on the typical progression (from the first to the thrid methods) for exploring the Idea Wing Chun way by a learner.