The principal theme of Samurai of Gold Hill is that of "strangers in a strange land." This theme emphasizes the problems people have when they feel that they are different from those around them, as well as the excitement people experience when they explore a new and different world. The other themes—racial discrimination, cowardice, and sexism—give the main theme its focus and help to clarify the relationships between the novel's characters.

At the start of the novel, Koichi already finds himself alienated, even though he is in his own town. His side in the civil war has lost, and his country now belongs to the enemies of his father and Lord Matsudaira. Too young to fight and die honorably as has his brother, Koichi finds himself surrounded by uncertainties; the samurai code of honor does not prepare him for defeat...