The quote "Deep rivers run quiet" from Haruki Murakami's "Hard-Boiled Wonderland and the End of the World" suggests that beneath a calm surface, there can be profound depths. This metaphor illustrates that individuals may carry complex emotions and thoughts hidden beneath a quiet demeanor. It highlights the theme of duality between what is visible and what lies beneath, a common motif in Murakami's work.

The phrase emphasizes the importance of recognizing the hidden complexities in people and situations. Just as a deep river flows quietly, so too can a person with depth appear tranquil on the surface while harboring rich inner lives that shape their experiences and perceptions. This duality invites readers to look beyond surface appearances to understand the deeper currents of emotion and thought that define human existence.