Neither of these images displays what I'm talking about. In the first, uke has something resembling what I'm talking about, but it's because kuzushi has already occurred, and O'Sensei has an erect posture, not what I am referring to. In the second, O'Sensei is leaned slightly forward, but is clearly in the midst of his movement and technique and is not displaying the posture I'm referring to.
Typically, I see this posture before engagement, at an intermediate step with a pause when technique is done step-wise or "kihon" as they say, and quite often as a finishing posture. Also, it is quite prevalent in many videos of Iwama weapons kata.