Board Thread:General Discussion/@comment-20311922-20130916143753/@comment-11051098-20131002230245

Maybe, but there's at least 3 captains present at a captain exam. Maybe he could have requested that only the captain-commander saw it, but it doesn't sound right to me.

The option I find most likely, especially since he said Ichig was the second to SEE the Senkei-technique, is that he showed and maybe demonstrated it to Ginrei. Ginrei, or a powerful opponent he had to use Senkei to kill.