At the end of the Shotokan version there is some shifty footwork and shuto uke following the second large circular arm motion and shifting front stance. I believe that this second circular motion is meant to be a knockout strike. The knife hand sequence that follows is the follow up in the case that your attacker is only stunned. Your stunned attacker goes for a takedown. You see this happen all the time in MMA fights. You even see very stunned guys trying to take down the ref sometimes. The first shuto uke is to gain control. You then take the opponent to one side to unbalance him. You see this same principle displayed by Muay Thai fighters in the clinch. They will move the opponent side to side and use kicks similar to those in Tekki Shodan/Naihanchi to set up throws. As you do this you turn your hand palm up and slip it under the back of his collar to grip. Shift forward and use the back leg of your knife stance to trip him. As he falls forward you cradle his head with what was the knife hand and perform the final shuto uke. The combo of this hand motion and the opponent's body weight will result in, best case scenario (for him) a severe neck crank and at worst a broken neck.
This bunkai raises a few questions. First, is it useful to know in today's society? If I can pull this off, couldn't I have gotten away? Have we moved beyond self defense here into a realm of techniques that may only be useful to a handful of special opps guys? These and a plethora of other such questions come to mind but when ever I practice this kata, it is this bunkai I am meditating on. So all that aside, does anyone have any ideas on how one might drill this without seriously injuring training partners? Despite its limited utility for self defense I have to admit that I really, REALLY, like this bunkai and I would like to drill it but I am kind of drawing a blank. Thanks in advance for any input you guys might have. Also, feel free to write about your own bunkai for this sequence as well.