Bankai, is the second and final upgrade for a Zanpakutō. To achieve the level of Bankai one must summon and subjugate their Zanpakutō spirit then beat it in a fight. To do this the Shinigami must force the Zanpakutō to manifest in the real world as opposed to conversing with them in their inner world. Usually it would take a Shinigami ten years to reach this level, and even more years to master it.

To start say either "Create me a Zanpakutō" or/then "Create me a Bankai."