Overview
An interesting technique that seems to have a single purpose - to jab at the throat. Probably more theoretical than practical as there are so many better ways to achieve identical results with the risk of a broken thumb.
Used in these katas
Unknown
Striking targets
Front of the throat
Technique
Open the hand, jab throat. The gap between the forefinger and thumb neatly guides the strike in.
Strengths
Creates a nasty shock, without the necessity of serious injury
Weaknesses
The thumb is extremely vulnerable
Doesn't seem to have any other uses