Uke enters to strike 6th form.
Nage enters moving slightly to one side of the attack. Uke changes the angle slightly to match the sideways movement but as Nage irimi's in deeply he further impacts Ukes posture using a blow with the palm of the hand into Ukes ribs. It is the follow through with the whole body which makes this technique work.

Nage = Sensei Brad Beeden.
Uke = Sensei Andy Lyon.
Clip Ref=ir13