Thearos wrote on Dec 8
th, 2009 at 11:20am:
I still think hooked on index, and released from between third and fourth fingers. Try it !
Doubtless it could be done either way and what the artist actually intended to portray may not be possible to ascertain.
What made me notice it in the first place was the previously mentioned photos of Kenyan slingers and also an illustration in a Russian language work on slinging referenced from the homepage.
• Shooting Techniques for the Sling and the Methods for Holding it (in Russian) (english translation)
The text is in Russian which I don't speak, and only partially understand from its similarity to Polish, but I was able to wade through some of it. Amongst others, it shows a two finger grip with loops on index and middle fingers. How the release is accomlished without losing the sling as well may be explained in the text but is beyond me. However the two raised finger grip is very similar to that employed by baseball pitchers. They add to the ball's final velocity by flicking it with their fingertips. If slinging is considered as merely enhanced throwing, there may be scope for incorporating methods used by arguably the world's best throwers into one's technique.