When does ichigo's dad tell ichigo about his mom's past?

Ichigo's dad, Isshin Kurosaki, reveals the truth about Ichigo's mother, Masaki Kurosaki, during the "Soul Society" arc of the "Bleach" series. This revelation occurs when Ichigo confronts the reality of his family's ties to the Soul Reapers and the significance of his mother's death. Isshin explains Masaki's background and her connection to the Soul Society, deepening Ichigo's understanding of his own powers and heritage. This moment is crucial for Ichigo's character development and his journey as a Soul Reaper.