Those attracted to Buddhism were not content to leave the question of what lies beyond death (or before birth) unanswered. They were deeply dissatisfied by Confucian agnosticism and Taoist fatalism regarding why we are born, where (if anywhere) we go when we die, why there is so much injustice in the world, and whether our moral and spiritual strivings mean anything in the face of death’s inevitability. The humanism of the indigenous Chinese traditions was very realistic and practical, but it tended to leave an existential void that Buddhism seemed better able to respond to with its teachings of rebirth and the process of sowing and reaping the effects of one’s causes over many lifetimes. Though imperfectly understood, at least at first, Buddhism gave people a sense of hope, responsibility, and meaning by teaching that life did not end at death and that the course of our lives is not random or the product of some arbitrary fate (whether endowed by Heaven or the Tao) but is determined by our own actions in sowing the seeds of good or ill that will come to fruition in present or future lifetimes.

Nichiren, like many other Buddhist teachers in East Asia before and after him, praises the humanistic virtues and civilized arts that the Confucians and Taoists taught, but in the end he too finds that their teachings are limited to only the present lifetime and that they do not address the debts owed from previous lives nor do they teach anything pertaining to the lives to come.

They may be called saints as far as their teachings for our present lives are concerned, but they cannot be called saints when we see that they know nothing about our previous or future lives. They are not different from ordinary men who cannot look at their backs or blind men who cannot see even their fronts. … But they are not true saints because they do not know the past and future. They cannot save the future lives of their parents, lords, and teachers. Therefore, we can say that they do not know the favors given to them by their seniors.

The Trapusa and Bhallika Sūtra, another apocryphal Chinese sūtra composed in the year 460 by a monk named Tan-jing, equated the five major precepts of Buddhism that enable one to be reborn as a human being with the five constant virtues of Han Confucianism. This became a popular theme taken up by later East Asian Buddhist writers. In the ninth century work Inquiry Into the Origin of Humanity by Zongmi (780-841) the equation of the five precepts and five constant virtues is put forth in the following formula: “Not killing is benevolence, not stealing is righteousness, not committing adultery is propriety, not lying is trustworthiness, and, by neither drinking wine nor eating meat, the spirit is purified and one increases in wisdom.” Nichiren also assumed this equivalence and alluded to it in works such as The Cause of Misfortunes (Sainan Kōki Yurao, considered a trial essay for Risshō Ankoku-ron):

Prior to Buddhism being introduced in China sage rulers such as the Yellow Emperor governed their kingdoms by means of the five virtues. After the introduction of Buddhism we can see these five virtues are the same as the five precepts of Buddhism prohibiting killing, stealing, adultery, lying, and drinking liquor. Ancient Chinese sages such as Lao-tzu and Confucius are the three sages whom the Buddha dispatched to China in order to propagate a Buddhism adapted to suit the land in the distant future. Therefore, the loss of kingdoms by such rulers as King Chieh of Hsia, King Chou Hsin of Yin, and King Yu of Chou through violating the five virtues equals violating the five precepts.

Also, to be fortunate in being born a human being and becoming a king is due to the merit of having observed the five precepts and the ten virtuous acts. Although non-Buddhist scriptures are superficial in teaching, not preaching the cause-and-effect relationship between merits in the past and rewards in the future, those who observed the five precepts and ten virtuous acts became kings. Accordingly, when people transgress the five virtues, heavenly calamities and terrestrial disasters will occur in succession.

As far as Nichiren and other East Asian Buddhists like Zongmi, or the Tiantai patriarchs Zhiyi and Zhanran were concerned, the reality behind the Confucian teaching of the Mandate of Heaven was not the collective will of the ancestors or the inscrutable workings of nature, but the unfolding of the law of cause and effect. Cause and effect operate according to the nature of one’s deeds for better or worse.