Board Thread:Questions and Answers/@comment-28648393-20160616142328/@comment-29640778-20160815072751

Ichigo's bankai should be revealed as him pulling in the reatsu already used during a fight. (This explains his rapid growth during battle and why his reatsu couldn't be sensed by Aizen while using the full extent of Getsuga.) Ichigo has already shown he can come back from death so Yhwach could 'see' his victory and get defeated after 'winning'. (Ulquiorra fight/Eyeball monk talking about the nature of Ichigo's ability) Ichigo is capabable of reflecting attacks against him though he's never consciously done it. (Explaining why he's rediculously durable and foreshadowed by Tenjirō Kirinji)