I'd like to discuss twin fist vertical punch.
I think I have seen a picture of Funakoshi demonstrating this movement, I tried to find it but so far haven't been able to. However, What do people have to the application of this, As a punch, it seems fairly awkward with the angles looking off and even the fists would surely get in the way of each other trying to get a decent shot.
When I have been looking of this I have thought about a collar grab, both hands grabbing either side of the collar something like a Maui Thai clinch but different.
and eye gouge, with either hand applying the gouge. this is a fairly small target so maybe by doing it with both hands gives a better chance of one being able to secure the grip.
In Toi Gye, the movement is followed up with a front kick double punch. So I would say that either technique would open up this follow up.
Here is a video of the mentioned pattern, vertical fist is the 8th movement.
very interested to hear others thoughts on this