This "Ichinen Sanzen Gohonzon" bears a passage from the fifth volume of Miao-lo (Chin. Zhanlan or Chan-Jan, Jap. Myoraku 711~782) Annotation on the Maka Shikan (Chih-i's Great Concentration and Insight; Jap. Shikan-bugyo-den-guketsu).
The passage is translated into English as, "you should understand that one's life and its enviromment are the entity of ichinen sanzen (or: at a single moment encompass the 3000 realms). When one attains the Buddha way, one's body and mind at a single moment pervades entire realm of phenomena." This passage is also quoted by Nichiren in his treaty (abbreviated title) "The object of devotion for observing the mind" (Jap. Kanjin Honzon sho).
--by Luigi Fini, author of an upcoming book about this GohonzonShu
This Gohonzon is also discussed in jap. at