Board Thread:Questions and Answers/@comment-9826910-20130618064245/@comment-11051098-20130722180856

What does OJT mean? :P

If Ichigo should learn to seal Zangetsu, I wonder what its release command would be. Isshin has "Burn", and seeing as Ichigo have already "inherited" a similar Zanpakutô name and one of his attacks, I'd say there's a good chance he'll end up with a similar release command as well.

Regarding the name, I wonder if none of the captains who held their position since Isshin was a captain, have seen the connection there. Byakuya for one has heard Zangetsu's name. But we don't know how long Isshin was a captain. The period of time he was captain, could have been relatively peaceful, and he wouldn't necessarily have needed to release his Shikai. And even if he did, it could have been on missions with his squad with no other captains around to hear it.