The challenge of assimilation stands as a central theme in the novel and is exemplified in the relationship between Doc Hata and Sunny. Both Doc Hata and Sunny have faced the challenge of assimilating to a new culture. However, they each responded differently to that challenge, and their different responses have contributed to the strain in their relationship. When Doc Hata immigrated to the United States, he did so by choice. He intentionally sought out a new life, and he approached the process of assimilation with meticulous devotion. Because he wanted to play an active role in the Bedley Run community, he readily adopted the values and behaviors of the community. Sunny, by contrast, did not come to the United States by choice. Furthermore, she was already seven years old when Doc Hata adopted her, which meant she was old enough to have learned the norms of Japanese society and feel comfortable communicating in the Japanese language. Everything in her world was turned upside down when she moved to Bedley Run. And though she clearly adapted to her new life in many ways and learned English fluently, she never fully assimilated to the values and behaviors of Bedley Run, which created conflict with her well-adjusted father.
Doc Hata frequently feels preoccupied by questions about the relationship between parent and child. Many of his questions stem from his disastrous relationship with his rebellious adoptive daughter, Sunny. He wonders whether Sunny turned out the way she did because of how he raised her or because of some predetermined characteristic. At the time when she left home, Doc Hata placed the burden of responsibility on Sunny, but in the thirteen years since then, he’s come to understand the role he played. Doc Hata knows that he had reservations about Sunny when he first met her, and he’s also increasingly aware that she sensed his hesitation and consequently felt unwelcome in his home. As Doc Hata attempts to reconnect with Sunny in the novel’s present time, he wonders why he’s rarely felt the kind of unconditional love for Sunny that he imagines a parent would have for their biological child. As an adoptee himself, he knows what it feels like to perform filial love for an adoptive parent yet still feel like an orphan. Even so, Doc Hata does feel an authentic outpouring of love for his grandson, Tommy, rendering the dynamics of parent and child even more mysterious.
One of the central themes Doc Hata draws out while looking back on his life relates to the danger of not taking decisive action when it really matters. Throughout his life, Doc Hata has repeatedly failed to act spontaneously from a deep sense of love or duty, and much of A Gesture Life focuses on these key moments of failure, particularly in his relationships with the Korean comfort woman, K, and his American love interest, Mary Burns. Doc Hata has also consistently let down his adopted daughter, Sunny, whom he failed to discipline and allowed to run away from his house without even trying to stop her. At multiple points in his life, others have criticized him for living a life of gestures—that is, for always hiding behind expressions of politeness that give the appearance of action but really just enable him to avoid responsibility. As Doc Hata comes to grips with the many times he’s stepped away from real responsibility, he longs to redeem himself. This longing for redemption drives him to try to repair his relationship with Sunny and culminates spectacularly during a scene in which he saves the lives of Sunny’s son, Tommy, and his close friend, Renny.