This video looks at the last three shuto-ukes (“knife hand blocks”) as found in Shotokan’s Bassai-Dai, Wado-Ryu’s Passai, etc. A comparison with other versions of Bassai / Passai will reveal that the second shuto (the one where you are “not looking”) is not there in most versions. It therefore seems to me that the “push” we see in other versions of the form has been stylistically over formalised into a distinct shuto-uke in the versions of the kata that posses that movement i.e. it is an “error” in transmission.
The bunkai sequence shown in this clip acknowledges that, but nevertheless makes use of the motion in a way that both fits with the modern version of the kata and uses essentially the same bunkai as the versions with the more subtle push. This enables the karateka to have an effective purpose for the modern version (i.e. the kata can remain as is) that also retains a connection to the underlying concept as demonstrated by other versions of the kata.
The video was filmed on my iphone at a seminar in Stuttgart, Germany. The clip is shorter than intended because I ran out of storage space! I nevertheless think the clip is easy enough to follow and should still give the general idea. As always, this short clip cannot explain the details nor can it show how such methods fit within the wider combative and training methodology. It is what it is :-)
All the best,
PS The YouTube link can be found HERE