What is the theme in The Samurai's Garden by Gail Tsukiyama?

Coming of Age is the main theme of the book. Stephen is actually a mature young man when he prepares to spend time at Tarumi recovering from tuberculosis. But he emerges more so, due partly at least to his own interaction with others and their impact on him. The story begins with Stephen dreading the trip and feeling as though he's being exiled. Despite those feelings, he's anxious to be kind to the old caretaker of his family's beach house and he and Matsu soon find a common ground. Their time together makes Stephen realize that he knew nothing about Matsu as a young man when Stephen's family visited the beach house on vacation. He has a similar encounter with Sachi—a friend of Matsu's who lives in Yamaguchi, also known as the Village of the Lepers.