Jung-Sum is the adopted second brother of the family. Whereas the only daughter, Jook-Liang, repeatedly hears how useless and ugly she is, Jung-Sum receives praise. He is handsome, and, as a male child, he carries part of the family heritage. He feels this role in an almost physical way when he receives his elderly uncle's secondhand coat. Rather than being ashamed of his hand-me-down, Jung-Sum reflects his culture's respect for family, proudly viewing the coat as a type of "armor."
In the novel's second part--narrated by Jung-Sum--we learn about the title image, the jade peony, which is connected with his grandmother Poh-Poh's gift for storytelling. Whereas his sister is fascinated by Hollywood glamour, Jung-Sum is fascinated by Poh-Poh's short, sad jewels of stories. Jung-Sum recalls her collection of tiny, exquisite jade carvings. Her favorite is the coin-size peony, her lucky spirit color, which Jung-Sum considers helps hold her memories in its intricate petals. That Choy puts the description of the object of the title in Jung-Sum's voice suggests that this character is particularly noteworthy.
Jung-Sum had been adopted into the family at the age of 4 after his parents died, and his early memories sometimes resurface, as when he recalls how he would search in closets and behind family members for his own parents, expecting them to come back for him. Scars on his back hint at past abuse, and in a boxing match as an adolescent he suffers vivid flashbacks of being beaten by his birth father.
The most dramatic revelation in Jung-Sum's chapters is his becoming aware of his homosexuality. Poh-Poh realizes early on that Jung-Sum is different from other boys, comparing him to the moon, where most boys are like the sun. To make up for this perceived difference and to toughen up his delicate hands, Jung-Sum takes up boxing. He admires the young boxing coach, Frank Yuen, and eventually and dramatically realizes that he is also attracted to Frank.