The rider has just come out of a heelside turn and is traversing across the fall line and getting set up to make their toeside turn. At this point, the rider is riding the uphill, heelside edge with both toes raised. With their weight shifted slightly forward to weight the nose of the board, the rider will first relax the heel pressure of the front foot, allowing the front of the board to flatten out. This allows the nose to start dropping toward the fall line. As the entire board enters the fall line, the rider gently relaxes the rear foot as well so there is a brief moment where the board is flat based and pointing down the fall line.
At this stage, known as the control phase, the rider will then push down on the toes to pressure the toe edge of the board with the front foot. This puts a slight twist in the board engaging the sidecut at the contact point and really beginning to steer the board up and out of the fall line on its toe edge. Immediately following the establishment of the turn, the rider will gently and gradually increase the toe pressure with the rear foot to follow through and complete the turn. Without this application of pressure with the rear foot, the tail of the board will slip to the outside of the turn and cause the rider to spin out of control. You exit this turn fully on the uphill, toeside edge.
As always, incredibly useful stuff!
Perhaps you could address timing of turn initiation with respect to position relative to the fallline? For a season or so, I think I waited to long to engage the next front foot edge (e.g., engage front toe side edge in heel to toe turn). I would wait until I was almost parallel to the fall line before I went from front neutral to front engaged (was afraid of edge catches).
An instructor last season suggested a stop sign (octagon) geometrical metaphor for initiation (slashes are snowboard track, dots for spacing only):
___ / B1
So clearly, traversing A is not perpendicular to the fall line (C) but represents whatever angle you are on across the slope. In your explanation above, I think I am supposed to go front foot neutral at A, let board drift toward fall line during early B1, and then engage the new front edge later in B2 but before C. What held me back for a season was waiting too long to engage that new front edge.
I still rely on "inclination" as you describe above (extending knees at C and leaning over edge, bending knees at late D and E) and have not yet progressed to true "angulation" as you describe above.
Is the above consistent with your explanation? Any further timing suggestions? Is timing different for inclination verus angulation?