Tsuinkai

Tsuinkai (ツイン解, Twin Release) is a form of release usable by the s of Project Nijū, which combines both their zanpakutō's respective releases.

Overview
Tsuinkai is not to be mistaken for a seperate release of zanpakutō, as it is simply both of the wielders zanpakutō released at the one time so both releases meld into one temporarily. There are two known stages of Tsuinkai currently known: The "Imperfect stage", where the release is only half that of normal, and the "Perfected stage", which melds both releases seamlessly into one another; thus transforming the user in a multitude of ways.

To perform Tsuinkai the modified soul in question must be able to release both their zanpakutō into Shikai, meaning the individual must know the zanpakutō's name. This is not as easy as simply picking a name, as the living spirit of the zanpakutō already has its own name. Therefore, the Shinigami must be able to communicate and harmonize with their zanpakutō effectively, which requires being able to speak to the spirit within its world.

is the easiest way to commune with ones spirit in which to build harmony and a working relationship. But even then a perfected Tsuinkai is not something one can just achieve by simultaneously releasing both of their Shikai. That is how one initiates the Imperfect Tsuinkai, as Jinta Kanō found. Only by overcoming the natural barrier that forms between both spirits can one merge their powers seamlessly for brief moments, as Jinta explained.

When a Perfected Tsuinkai is released, a new, temporary zanpakutō spirit is born within the users inner world. This new being is a seamless fusion of the two spirits, and this bears characteristics of both, as well as a set of conjoined abilities; as well as each respective spirits own techniques. This new being also possesses its own name, as Jinta, wielding both Samazamahi (変火災, Varying Fire) and Nijigasumi (虹霞, Rainbow Mist), results in the creation of a being called Amaterasu (天照, Illuminating Heaven).

Behind the Scenes

 * The concept of Tsuinkai dates back to when the author first joined the wiki scene. His main character, Kenji Hiroshi, originally possessed two zanpakutō. The fanon Samazamahi and the canon Shiden, which could both be released at the one time, which was dubbed Tsuinkai.