Board Thread:General Discussion/@comment-12611839-20130718170314/@comment-36161973-20180712020319

No. No. No. … First of all Isshin never mentioned the exact name of the technique. All he spoke about was a final technique, the ultimate power of one's zanpakutō. Since „Old man Zangetsu“ wanted to *protect* Ichigo he didn't limit his power in such a life-threatening situation. His intention was to save Ichigo by all means possible: This was symbolised by Fused Zangetsu „killing him to save him“. It was the realization of Quincy/„Old man“ Zangetsu's desparate intent to protect him and letting him have his way / completely trusting him, relying on him, not fighting him which was necessary for his power to be unleashed. Also note the striking resemblence of Rukia's act of sharing her power with Ichigo with how Fused Zangetsu stabbed him; at the exact same spot (!!!). Remember Uryū using the Quincies' Final Style? That cost him his powers. Familiar? With his powers fused Ichigo's strongest technique was a mix of Letzter Stil (Last/Final Style) AND true Bankai allowing him a maximum release of all his powers in a single attack. This is Mugetsu. You could of course argue wether it is a good choice to do this as if you fail to aim etc you lose but it seems to be the right choice against Aizen.