Nichiren elaborates (see earlier) in the following passage:

“When one arrives at the origin teaching, because [the view that the Buddha] first attained enlightenment [in this lifetime] is demolished, the fruits of the four teachings are demolished. The fruits of the four teachings being demolished, their causes are also demolished. The causes and effects of the ten realms of the pre-Lotus Sūtra and trace teachings being demolished, the cause and effect of the ten realms of the origin teaching are revealed. This is precisely the doctrine of original cause (hon ‘in) and original effect (honga). The nine realms are inherent in the beginningless Buddha realm; the Buddha realm inheres in the beginningless nine realms. This represents the true mutual inclusion of the ten realms, the hundred realms and thousand suchnesses, and the three thousand realms in one thought-moment.”

To unpack the rather technical language of this passage, the “four teachings” here represent those other than the Lotus Sūtra. Their “effects” refers to the attainment of Buddhahood, or to the Buddhas, represented in these teachings, and their “causes,” to the practices for attaining Buddhahood, or to those still in the stages of practice. In terms of the ten dharma realms, “cause” represents the nine realms, and “effect,” the Buddha realm. “Demolishing” the causes and effects of the pre-Lotus Sūtra teachings and the trace teaching of the Lotus Sūtra means to demolish linear views of practice and attainment, in which efforts are first made and then Buddhahood is realized as a later consequence. The origin teaching   specifically, the “Fathoming the Lifespan” chapter with its revelation of the Buddha’s original enlightenment   is here seen as opening a perspective in which cause (nine realms) and effect (Buddhahood) are present simultaneously. It is passages such as this that led Tamura Yoshirō to assert that Nichiren maintained the notion of original enlightenment in the depths of his mature thought. (Page 264-265)