What is the theme in Debt of Honor by Tom Clancy?

Honor is the central theme of this book. A debt of honor refers to what is owed to a person or entity in order to maintain one's integrity or to sustain the principles of that person or entity. In this work, debts of honor are clearly in conflict. To Yamata, the debt of honor is owed his family and his country, and it involves somehow avenging the suicide death of immediate family