According to the novels, Yoruichi has manifested her Zanpakuto spirit and therefore possesses both Shikai and Bankai. However, she's stronger when using her Shunko. The novels further state that ...

One of the major highlights from the latest Bleach TYBW episode, titled Shadows Gone, was Shunsui Kyoraku summoning Okyou (Kyokotsu) to return Nanao her ancestral Zanpakuto, Shinken Hakkyoken.