This is the second last Single Whip in the Yilu routine. It is different from other Single Whip moves. Before, stepping to the left, the right hand does a deep positive circle and goes way down before coming to the finished position. Hong changed it to this way through his personal experiences. Here is how it is applied. Notice that the left leg did not step forward as required in the form.
Yilu 68. Single Whip
Previous post: Go ahead… push me over…
Next post: Yilu 62: Elbow Strike