Chang-rae Lee, in a A Gesture Life, uses the limitations of first person point of view to create tension in the story. Because his narrator is unreliable, the reader must do a certain amount of detective work to figure out the truth: this tension engages the reader and advances the plot. For instance, we have the sense that Doc Hata is lying to himself about why his daughter left, about the sale of his business, and about what happened during the war. We keep reading in the hopes of putting together the truth.
In a similar way, the unreliable first person narration in A Gesture Life helps build character. From the beginning it's unclear whether the character is Korean or Japanese; when we realize that he lies to others and to himself about his nationality, we understand that he has a deep-seated issue with his own identity. This fact complicates his decision to adopt a Korean girl and sheds light on the conflict between Doc Hata and his adopted daughter.
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