Secret training ground (Sōkyoku)

The cavern hidden beneath Sōkyoku Hill where Urahara and Yoruichi played and trained as children. Here Yoruichi brings Ichigo to achieve Bankai in three days with the Tenshintai.

The Tenshintai materialises a Zanpakutō's spirit in the outside world: Ichigo must subdue it instead of merely hearing it. Renji trains in the same cavern too, after his defeat by Ichigo, to complete his own Bankai.