User blog comment:Njalm2/The Beauty of Zanjutsu/@comment-136273-20150410194427/@comment-3403804-20150410195652

The release isn't meaningless, it's permanent, much like how Ichigo's Bankai was in his final battle against Aizen: which I'll be going into with a specific section later on. Once you fully master Jinzen and Bankai, from my perspective, the power spike you ordinarily gain from Bankai which is about 5-10 times your base strength, becomes permanent as well. That's not so say that there can't be a transformation of sorts, they might have to limit their power in stages so as to not cause devastation from the weakest little thing, sorta like how Toguro restrained his power to manageable levels in Yu Yu Hakusho. Or, if you're a DBZ fan, how Frieza "weakened" himself with his transformations because he couldn't control himself while in his final state.

I might also go into detail about the role your forms would play, because they would indeed be relevant here too. If Zanjutsu is the content of a bottle, then the forms are the bottles themselves, they're how your characters powers manifest while in combat. As an example, with that form of yours. Koseido, Takumi would be able to create literal maelstroms and twisters of fire, due to the movements emphasized by Koseido, without that form, his slashes would simply produce Getsuga Tensho like waves. Which is much more limited and restrictive.