If you are watching the original series or the recent Thousand-Year Blood War (TYBW) arc, Episode 9 is highly regarded:

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This episode is considered "peak fiction" by fans. It features the intense start of the battle between Zaraki Kenpachi and Retsu Unohana , revealing Unohana's brutal past as the first "Kenpachi". Critics noted its excellent animation and high-stakes character development. Where to Watch Safely (Legal Options)

This is a pivotal, emotional episode centered on the battle against the Grand Fisher , the Hollow that killed Ichigo's mother. It is praised for its "Memories in the Rain" theme and for providing deep insight into Ichigo's motivation.

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