Board Thread:General Discussion/@comment-4976518-20140808063123/@comment-24769684-20160305034206

Aizen only needs to activate Shikai in front of his target to be able to hypnotize them, and his illusions affect all senses. Ichigo didn't see these illusions because he had never seen Aizen's Shikai. Nowhere was it hinted that Bankai was ever involved

And by your logic, wouldn't his Shikai be completely ineffective without using Bankai?