False Zenkai

False Zenkai is the "false" version of the original Zenkai state. When someone masters Shukai to a certain level, they believe they have obtained Zenkai, however, no, they have not. The False version doesnt compare to the true Zenkai state but is stronger then Shukai or Tenkai.

The Grand Supreme Kai, Irounaku, who created the true Zenkai, made this form avalible to all zanpaktous but kept the original Zenkai state secret to only him, even Yhvh not knowing of it (If you can even believe that). Irounaku shared the original form with Seireitou only and made this form avilible to all others.