Board Thread:Questions and Answers/@comment-26955371-20150920164120/@comment-26955371-20151009164319

You have a point here but there is still nothing that proves that he lied to Ichigo, he was also refering to his Zanpakuto ( not his Bankai ) when he talked about his speed.

And even if Aizen wasn't expecting Gin to attack, he should've seen it, but he didn't. And it was a superior Aizen to the previous who fought a serious Yoruichi.