Bankai Training

Bankai Training is an event that follows Ichigo's fight with Kenpachi Zaraki and preluding Rukia's execution.

Prelude
In the aftermath of his fight with Kenpachi Zaraki, Ichigo is left mortally wounded. Yoruichi finds him and transports him to a hidden chamber under Sōkyoku Hill, where she intends to keep him till he is healed, however, as she is explaining to him the nature of her flying device, they suddenly feel the Reiryoku of Byakuya Kuchiki near the Senzaikyū, where Rukia was being held. Ichigo is reminded of Ganju and Hanatarō, whom he sent to Rukia's rescue. He snags Yoruichi's device and leaves for the Senzaikyū. When he gets to the Senzaikyū bridge he finds Ganju already grievously injured by Byakuya's Shikai and Hanatarō and Rukia pinned down by his Reiatsu. Ichigo confronts Byakuya and challenges him. To everyone's amazement, Ichigo fights on an equal level with the captain in his pre-release. However, Yoruichi arrives just in time to stop Byakuya from using his release against Ichigo. She sedates Ichigo by inserting a tranquilizer into his open wound and then manages to escape the pursuing Byakuya, along with Ichigo, using Shunpo. She promises that in three days time she will bring Ichigo back, stronger than Byakuya. Yoruichi brings the anesthetized Ichigo back to Kisuke Urahara's secret training ground under the Sōkyoku Hill. When he wakes up, he is very cross with her, for having rescued him and him alone out of all his allies on the bridge, saying he was the one with the best chance of defeating Byakuya, and because of her actions Hanatarō, Ganju and possibly Rukia might be dead. Yoruichi tells him that he had no chance against Byakuya, and the presence of Jūshirō Ukitake on the bridge won't allow Byakuya to kill his allies or Rukia, who is his subordinate. She also explains that she could only carry one person and still hope to outrun Byakuya's Shunpo. She rescued Ichigo because she believes in three days time she could teach him a way to defeat Byakuya and rescue all his allies.

Renji awakens from his sleep in the prison cell where he is recuperating from his injuries. His Zanpakutō, Zabimaru materializes and urges him to get well soon so that they can fight Ichigo and Zangetsu again. Renji tells him that he no longer considers Ichigo his enemy, and has no quarrel with him. Zabimaru then asks who Renji intnds to fight. The next day Renji escapes his prison cell and disappears.

The training
Ichigo agrees to begin his training before he has fully healed from his injuries, although Yoruichi promises it would hurt quite a bit. Ichigo draws his Zanpakutō and gets into battle stance, but Yoruichi stops him and asks if he had ever noticed his Zanpakutō was always in a released form. Ichigo says he did notice it was larger than other Zanpakutō, and wouldn't change shape when he tried to release it. He remembered that Zaraki's Zanpakutō was the same. Yoruichi realizes he didn't know and assumes he must have not known about the second level release for a Zanpakutō. She explains that the second release is called Bankai, and that mastering it is one of the qualifications of becoming a captain of the Gotei 13. She tells Ichigo all the current captains besides one can perform the Bankai release, the one exception being Zaraki. The 11th Division captain is the only one in history to be made captain without even knowing the name of his Zanpakutō, but his raw strength and massive Reiryoku more than make up for this deficiency, as Ichigo should know full well. Yoruichi explains that while one's Bankai is dependent on the Zanpakutō's spirit and its wielder's strength and training, achieving a Bankai can boost one's power between 5 to 10 times. This is due to the fact that achieving the Bankai after attaining Shikai usually takes at least ten years of training. When Ichigo protests, saying he doesn't have ten years to train, Yoruichi calms him down and says she doesn't intend to use the proper method of training with him, but use a much faster yet far more dangerous method to get him to learn Bankai within three days.

After a long session, exhausted from the pain, Ichigo finds it hard to get back on his feet. Yoruichi encourages him