Rinju is the time immediately before one dies. The term is an abbreviation for "rinmyoshuji" (at one's death). Since ancient times, various customs and cultures concerning the acceptance and saying goodbye at one's death have been created for this critical time.
Although the books titled "Book of the Dead" that were written in Egypt and Tibet are known as the old literature that explains the meaning of dying, they do not necessarily focus on issues at the time of one's death. On the other hand, in Western Europe, the book known as "Ars moriendi," written in the late medieval period, explains what a person who is going to go through rinju needs to know. According to this book, the Devil intrudes on every deathbed, causing confusion of conscience and various afflictions. However, to fight such temptation, the God lets dying persons experience Heaven in advance and promises to atone for their sins. The attack of the Devil has been depicted in many drawings, distributed among the public. Many guidebooks on the art of dying argue that the person who attends someone's death should not give the dying person the illusion that recovery may be possible, but should try his or her best to help the dying person to accept the death naturally.
In ancient Indian Buddhism, Mujoin (monastery for rest of sick persons in Jetavana Vihara) was constructed at the northwest corner of Jetavana Vihara to accept the sick and dying persons. Daoxuan, who later played an active role in the period of the Tang Dynasty of China, wrote "Shibunritsu Gyojisho" (the "Ceremonies" Section of the Four-fold Vinaya) based on tradition handed down from India and therein discussed nursing the sick and seeing him or her through to the end. According to the writing, in the hall of Mujoin, a standing statue of Buddha is placed facing the west. On the hand of the statue, a five-color cloth is draped to the back, with the end of the cloth held by the lying sick person for him or her to pray for birth in the Pure Land. "Kannen-bomon" (the Method of Contemplation on Amida) written by Shandao in the same period of the Tang Dynasty discusses the relationship between the sick and persons who attend the sick. More specifically, the book argues that, although Zaiso (the state of agony) and Zenkyo (the state of religious exultation) appear in the sick person in turn in the stage of rinju, the person who attends the sick person must inquire about the states to him or her to record the answers and must chant nenbutsu (Buddhist invocation) together to help him or her to be able to die in the state of Zenkyo.
In Japan, Genshin (monk), who appeared during the mid-Heian period, took on the rinju theories proposed by Daoxuan and Shandaon squarely to use them as guides for attaining Jodo Ojo (Rebirth in the Pure Land). Quoting their theories in 'Manners at one's end' at the end of his book "Ojoyoshu" (The Essentials of Salvation), Genshin preached the manners of a life devoted to a Buddhist invocation that should be followed at the time of rinju, and as a result made a tremendous impact on later generations. One can find traces of how the manners at rinju took root by reading ojoden (stories of the attainment of rebirth in the Pure Land), which started to be made from the end of the ancient period to the medieval period. Various raigo-zu (images of the descent of Amida Buddha) that were created in a large number in the same period were also used as sacred symbols that promise birth in the Pure Land at rinju.
Some Buddhist scriptures preach the states of rinju in various ways.
For example, Ajaseojuki Brahma No. 10, Volume 10 of "Shugokokkaishu-darani kyo" argues the following. There are 15 states that lead one to die and suitably go to Hell. There are five states that lead one to become a preta. As shown above, the book describes the states that lead to each destination, such as 15 states for Hell, eight states for a preta, and five states for chikusho (Buddhist realm of beasts). The 15 states that lead one to Hell include giving an evil stare at one's husband/wife, men/women, and kenzoku (one's family and relations), groping in empty space by raising one's both hands, crying in tears without following the teachings of the kalyaana-mitra (one who offers spiritual friendship and guidance that is non-directive, non-denominational, and non-religious), not learning and knowing how to defecate and urinate, keeping one's eyes shut, and constantly covering one's head.
"Daichidoron" (Commentary on the Great Wisdom Sutra) argues that 'at rinju, those whose color changes to black will go to Hell,' and "Makashikan" (Mahayana Practice of Cessation and Contemplation) by Zhiyi of the Tendai sect in China also discusses that 'a change of one's color to black is compared to the shadow of Hell.'
Based on these Buddhist scriptures, Nichiren stated the following.
If that is the case, I thought I should learn things about rinju before other things, and when I collected, thought about, and used as a mirror the interpretations of Buddhist scriptures by those who studied and wrote about Buddha's entire teachings and by those who studied Buddha's such teachings and taught them to develop the personalities of others, comparison of the condition at the time people died, on the one hand, with the condition after that, on the other, gave no doubt of their correctness. (Myoho ama gozen gohenji [(Reply to the Nun Myoho])
As described above, he placed emphasis on the state of rinju, which he considered the conclusion where one's good deeds and evil deeds across three lives manifest themselves in Sansho (Three Proofs), and he considered that this state leads one to the future life, and determined that those whose state at death is good will become a Buddha and those whose state at death is bad will go to Hell.
However, Nichiren states as follows (Rinjuyojinsho). Those who practice the teachings of other sects will go to Hell even if they die in a good state. According to Section 860 in Chuseiron, even if such people die in right mindfulness chanting the name of the Buddha, there is no doubt that they will go to the Avici hell because of their great sin of slandering the Hokke sect. I say Sangai of the Zen sect died losing his voice as a matter of fact. Zenmui of the Shingon sect changed to black when he died, and Shandao of the Jodo (Pure Land) sect had the wrong view and became crazy when he died. The progenitors of other sects will end the same way, the meaning of which their disciples should know. A teacher is like a needle and his or her disciples and supporters are like a thread, which is exemplified as they die and go to Avici hell.
Based on these Buddhist scriptures, Nichiren criticized the progenitors of other sects such as the Shingon sect and the Ritsu sect and insisted on the superiority of his own school. Thus, some religious schools that inherit this teaching and propagate their schools by putting up the exclusive or self-righteous dogmas make ideological threats, which are perceived as a problem.