Board Thread:General Discussion/@comment-27110495-20160106235339/@comment-11051098-20160527141015

@ Dekoshu:

As far as I remember, it's always required to say "Bankai" when activating it. However, after one has achieved Bankai, one doesn't necessarily have to call out the release command and Zanpakuto name to release Shikai.

@ Alaba:

We saw Isshin use Getsuga Tensho twice while Engetsu was in its sealed state. It could be the same with Ichigo, we just don't know since Zangetsu has never had a sealed state, not that we know of.

It seems unlikely to me that his current twin blades is a sealed state, but Ichigo is a special case, so who knows.