Zokumyojyuho means treasured heirloom to atone life and indicates the teachings in "Nehan-gyo Sutra" (The Sutra of The Great Nirvana) defined by Tendai Daishi Chigi. Nichiren also succeeded this theory.
Nichiren described in "Teradomarigosho" (a letter document written by Nichiren in Teradomai of Niigata Prefecture) as follows:
Chigi divided teachings of Shakyamuni in his lifetime into Eight teachings including zo, tsu, betsu, and en, and defined that en is the most excellent teaching among all. Then, he compared Hoke-kyo Sutra (the Lotus Sutra) to life and Nehan-gyo Sutra (The Sutra of The Great Nirvana to treasured heirloom. Nehan-gyo Sutra preaches Shakyamuni's lifetime teachings again. Therefore, bussho josho (one of the Buddhist teaching about the status of reaching the Nirvana and its eternity) (en teaching) is just a repetition of en teaching that is the life of Hoke-kyo Sutra, so Nehan-gyo Sutra is the same as the former three Sutra (zo, tsu, betsu teachings that were preached before Hoke-kyo Sutra, that is, Kegon-kyo Sutra, Agon-kyo Sutra, Hodo-kyo Sutra, Hannya-kyo Sutra, and only that is what you should learn. Nehan-gyo Sutra is just treasured heirloom to atone life.
"Nehan-gyo" volume 18, 梵行品 describes as follows:
Sutras of Nehan-gyo can be summarized as 'Nehan-gyo is a secret that Nyorai (Tathagata) possesses and is not preached in teachings before Nehan-gyo. Possessing it is like having treasure to atone life by giving it to robbers or bad guys who come and want to kill you, so if bad Biku (Buddhist priests) emerge in the future and preach "Shakanyorai, Shikyajirai died, entered Nirvana, and no long exists in this world," then you should deliver this secret Nehan-gyo. If this Nehan-gyo does not emerge, the Buddhist law will disappear,' this is the original intention of the sutras. Therefore, strictly speaking, this sutra does not describe that Nehan-gyo is a treasure and Hoke-kyo is a life. Therefore, it is said that Chigi determined that Hoke-kyo is superior to Nehan-gyo and interpreted the sutras of Nehan-gyo.
In the period when Chigi was active and Tendai-shu sect prospered, the Nehan Sect that has its basis on Nehan-gyo became only a school sect and was impractical. Therefore, they did not have power to hold out against Chigi who made out these interpretation at full blast because he was excellent in both learning of religious doctrines and practice, and the Nehan Sect was taken over. However, in recent Buddhist Studies, some people point out that these were forceful interpretation (dogma) by Chigi.