It introduces the fundamental principle of legislation in the Tang Dynasty, "virtue as the foundation and punishment as the supplement," emphasizing virtue and rites as the root of governance while using penalties as a means of governance. This principle reflects the Tang rulers' people-centered philosophy of governance and represents a Confucianized concept in ancient legal systems. Virtue and rites complement each other with punishments, much like the alternation of day and night or the succession of spring and autumn.