How to Express Layered Time: The Challenge of Unkei and Seikai

In Daisuke Kojima's "Unkei's Tenpyo Revival: The Background of the Formation of the Hokuendo Hall Statues at Kofuku-ji Temple," under the section "3. Expressions Transcending Time and Space: The Tushita Heaven and the Tenpyo Revival," it is written as follows.

At the time of the Hokuendo Hall's founding, the intention must have been to give form to the Tushita Heaven, where Fujiwara no Fuhito was to be reborn. There, Maitreya, promised to attain great enlightenment in the future, was already depicted in the form of a Tathagata.(Omitted)Generally, it is understood that Maitreya in the Tushita Heaven will attain great enlightenment, descend to this world, and hold the three assemblies under the Dragon Flower tree after 5.67 billion years of contemplation. However, it seems that people in the Nara period sometimes imagined Maitreya in the Tushita Heaven as a Tathagata, and it is likely that the Maitreya Tathagata statue in the Hokuendo Hall at the time of its founding was also in the form of Maitreya residing in the Tushita Heaven. Perhaps it is a figure that foresees the future? Some view the fact that the Komokuten (Virupaksha) among the Four Heavenly Kings is not depicted holding a brush and scroll, which is typical of Tenpyo sculpture, as an implication that the location is the Tushita Heaven. However, since a Maitreya Bodhisattva statue was enshrined within the statue during the Kamakura period restoration, it is clear that, unlike at the time of its founding, they were consciously giving form to the figure of Maitreya who has attained future enlightenment. A vast amount of time is contained within the Maitreya statue.
*Tathagata: Refers to one who has completed their training and attained enlightenment. One who has come from the world of truth to the world of delusion to save sentient beings.
*Dragon Flower Three Assemblies: The three preaching sessions that Maitreya Bodhisattva is said to hold after descending to this world (Jambudvipa) 5.67 billion years after the death of Shakyamuni, attaining enlightenment under the Dragon Flower tree, and saving sentient beings. It is said that those who did not attain enlightenment through the teachings of Shakyamuni Buddha will join these sessions and attain enlightenment.
*Bodhisattva: One who practices in search of enlightenment. Originally referred to Shakyamuni before he attained enlightenment and his previous lives.

Regarding the part above, "since a Maitreya Bodhisattva statue was enshrined within the statue during the Kamakura period restoration," it is indicated to refer to the content of "Another Maitreya Statue: The Enshrined Objects of the Hokuendo Hall Maitreya Tathagata Seated Statue" by Ayaka Tomioka. What kind of Maitreya Bodhisattva statue was enshrined?

According to the dedication vow dated the second year of Kenryaku (1212), the Maitreya Bodhisattva standing statue enshrined within the statue is a "three-inch sandalwood" Maitreya statue that Sen-shin, who devoted himself to the creation of the Hokuendo Hall statues, had long carried with him, and it is said that a Buddha relic passed down at Toshodai-ji Temple was placed inside its head.(Omitted)It is known that Sen-shin, under his master Shin-en, also devoted himself to the restoration of Shoryaku-ji Temple in Nara, which was burned down during the Siege of the Southern Capital, but it was Unkei who created the principal image of Maitreya at Shoryaku-ji Temple's Shogan-in Hall in the second year of Bunji (1186), about 25 years before the creation of the Hokuendo Hall statues. Given these achievements and his style, there is an attractive view that speculates the Maitreya Bodhisattva statue enshrined in the Hokuendo Hall statue was also the work of Unkei.

The catalog has a detailed commentary page with photos regarding the "Maitreya Bodhisattva Seated Statue: Objects Enshrined Within the Statue."
Inside the head, a "black lacquer zushi (shrine)" (11 cm high) containing Sen-shin's "Maitreya Bodhisattva standing statue" and "dedication vow," along with a scroll called the "Hokyoin Dharani Sutra," are placed. Also, a "crystal bead" (about 4.3 cm) is enshrined in the body. This is the "Heart Moon Disk," which represents the "pure heart seeking enlightenment in Esoteric Buddhism."
Please check the catalog for details, but it is described there as "truly the culmination of Unkei, who is known for his devotion to the form of enshrined objects and the method of dedication."
It is not rare for Buddha statues to contain enshrined objects such as Buddha relics, Heart Moon Disks, and the wishes of the donors and others involved with the Buddha within their wombs. However, as mentioned in the commentary, one can see Unkei's outstanding ability in the fact that "a vast amount of time is contained" within the womb of the Hokuendo Hall's Maitreya Bodhisattva statue, that is, in the fact that he "consciously gave form to the figure of Maitreya who has attained future enlightenment."
However, I believe that the sense of "vast time" in the salvation of sentient beings was something that existed within the spiritual foundation of the people of that time. This is because I remembered that there was another person who attempted to "consciously give form" to the same thing, not through sculpture, but through language and painting.

From the expression and conception of the "Ippen Hijiri-e" (Illustrated Biography of the Holy Man Ippen) created in the Kamakura period, I have been considering the ideology that Seikai, the author of the text (who was likely also the person who supervised the composition of the entire picture scroll), tried to depict. One conclusion I reached was that Ippen, a "holy man" of the modern age, is connected to the lineage of past "holy men," and that it suggests what kind of person the "holy man" who will appear in the future after Ippen's death will be, and preaches that the salvation of Amida Buddha is realized within such a "vast time" period.

Unkei and Seikai must have understood well the meaning of the Buddha's teachings becoming "art" such as Buddha statues and picture scrolls, and existing before our eyes across hundreds of years. Thinking of that, I was also struck by the subtitle of this special exhibition, "The Space of Prayer."
At the end of the previously cited "Another Maitreya Statue: The Enshrined Objects of the Hokuendo Hall Maitreya Tathagata Seated Statue" by Ayaka Tomioka, it is written as follows.

In the dedication vow by Sen-shin enshrined in the zushi, it is stated that by enshrining the Maitreya Bodhisattva statue he had long carried with him into the Hokuendo Hall Maitreya Tathagata seated statue, he wishes that his parents, his master, and all the sentient beings who connected with him and devoted themselves to the restoration of the Hokuendo Hall statues will be able to worship the Hokuendo Hall statue in the future when Maitreya descends to this world, that is, to meet the Maitreya Tathagata who saves through preaching.(Omitted)When you worship the Hokuendo Hall Maitreya Tathagata seated statue, I hope you will also think about the sincere prayers that transcend time and space, which are contained in the two Maitreya statues.

The "Ippen Hijiri-e" concludes with the words, "Even if time passes and things change, if one seeks the past and knows the new, will it not be a model for a hundred generations and a leader for a thousand years?," assuming a time of "a hundred generations."
*A hundred generations: A very long period. Eternity.
*Model: A standard. An example.
*Leader: A person who stands at the head of others. A person who leads others and becomes their head.

Through the space of the Hokuendo Hall (this exhibition that recreates it) and the record of the travels of Ippen and the Ji-shu sect depicted in the picture scroll, we too are incorporated into the "sincere prayers that transcend time and space." Both Unkei and Seikai must have intended this.

[References]
・Tokyo National Museum, Hosso Sect Head Temple Kofuku-ji, Yomiuri Shimbun, "Special Exhibition: Unkei - The Space of Prayer - Kofuku-ji Temple's Hokuendo Hall" (Published by Yomiuri Shimbun, September 9, 2025)
・Kanagawa Prefectural Museum (ed.), "National Treasure: Ippen Hijiri-e" (Published by Yugyo-ji Temple Treasure House, October 9, 2015)