It is said that Nanboku satirized the unreasonable hierarchical society indirectly and severely by depicting the outcomes of main two characters' lives; although Sangoro is just a ruffian of the common people's town Fukagawa, he cheats a person to save his father's ex-master who has been in difficulties; however, although Gengobe murders many people by passions, at last he sheds his disguise and as real himself Kazuemon, joins the group of the loyal samurai with no shame.
深川の無頼者たちを仲間にする三五郎が、父の旧主の困窮のために人を騙すのに対して、結局のところ痴情によって多数の人を斬り殺す源五兵衛が、最終的には数右衛門に戻って晴れて義士の列に加わる点において、不条理な身分の違いを、暗に、しかし強烈に、南北は皮肉っているとされている。