Hand position for Sanchin or Juji Uke
While watching one of the Gracie Brothers teaching films, which I do to gain training ideas, I saw a vulnerability in the lead action. As he was well covered on the entry, once he transitioned into the next action, the opportunity presented itself. Now with conventional striking actions or power based strikes, it would not have a great affect as noted in the film, however this is where Kyusho really shines, in it's powerful dysfunctional ability with small directed actions and force. Something conventional arts do not train and therefore comprehend or learn to counter.
Of course this or any method or martial application must be trained incessantly to become a natural and automatic response, even then nothing works 100% of the time. However this same action may be used in standing application as demonstrated, the mount or the guard position as well. So there are never one chance applications, they are numerous and also must be trained.