Nichiren spoke of his object of worship as embodying “the three thousand realms in a single thought-moment as actuality,” a statement that may be understood in two ways. First, as underscored by recent studies in Buddhist art history, icons and mandalas in premodern Japan were seen not as merely symbolic or representational but as participating in and actively embodying the sacred powers of the beings or principles they depicted. Nichiren explains this idea in terms of the concept of the Buddhahood of grasses and trees (sōmoku jōbutsu), or more broadly, of insentient beings, a principle encompassed by the doctrine of the three thousand realms in one thought-moment:

Both inner and outer writings permit the use of wooden and painted images as objects of worship, but the reason for this has emerged [only] from the T’ien-t’ai school. If plants and trees did not possess cause and effect [i.e., the nine realms and the Buddha realm] in both physical and mental aspects, it would be useless to rely on wooden and painted images as objects of worship. … Were it not for the Buddha-seed which is the three thousand realms in one thought-moment, the realization of Buddhahood by sentient beings and [the efficacy of] wooden and painted images as objects of worship would exist in name but not in reality.

For this reason, Nichiren insisted that only the Lotus Sūtra, the textual source of the ichinen sanzen principle, was efficacious in the eye-opening ritual for consecrating Buddha images. (Page 276-277)