Day 1 covers the first half of Chapter 1, Introductory

Having last month consider what Maitreya Bodhisattva thought this wonder displayed by the Buddha, we consider what the rest of the crowd thought.

At that time the congregation included the four kinds of devotees: bhikṣus, bhikṣunīs, upāsakās and upāsikās. They also included gods, dragons, and other supernatural beings. Maitreya Bodhisattva, wishing to have his doubts removed, and also understanding the minds of the congregation, asked Mañjuśrī:

“Why is the World-Honored One displaying this good omen, this wonder? Why is he emitting a great ray of light, illumining eighteen thousand worlds to the east, and causing us to see those beautifully-adorned worlds of the Buddhas?”

Nichiren addresses the significance of the Introductory chapter and the position of the Lotus Sūtra in “Shugo Kokka-ron, Treatise on Protecting the Nation”:

[I]t is stated in the first “Introductory” chapter of the Lotus Sūtra that when the Buddha showed a potent omen of emitting a ray of light from the white curls between His eyebrows, Bodhisattva Maitreya saw Buddhas of the numerous worlds in the universe expound major sūtras in five periods He then asked Bodhisattva Mañjuśrī what this all meant: “The Buddhas, Saintly Masters, the Lion-like Ones, expounded the most wonderful sūtra. I also saw them teaching many billions of bodhisattvas with pure and gentle voices.” This indicates that the first preaching of the Buddha was the Flower Garland Sūtra for bodhisattvas. Also, in the “Expedients” chapter of the Lotus Sūtra the Buddha refers to His experience upon attaining enlightenment stating, “Sitting under a bodhi tree for the first time, I meditated on the tree, strolled about … then various heavenly beings such as the King of the Brahma Heaven, Indra, the Four Heavenly Kings who protect the world, and Great Freedom God and billions of their retainers respectfully held their hands in gasshō, bowed and requested Me to preach. This passage from the Lotus Sūtra indicates when the Flower Garland Sūtra was preached. Hence the first fascicle of the Flower Garland Sūtra includes such names as moon god, sun god, Indra, King of the Brahma Heaven, and Great Freedom God, all of whom attended the assembly of the Flower Garland Sūtra. …

Āgama (Hinayana) sūtras were preached following the Flower Garland Sūtra. … Regarding what sūtras were preached after the Flower Garland Sutra, the “Introductory” chapter of the Lotus Sūtra states, “To those who suffer, hating old age, sickness and death, the Buddha preaches the teaching of Nirvana, showing ignorant people the way to tranquility and extinction of worldly passions.” In the “Expedients” chapter of the same sūtra, it states, “The Buddha went to the Deer Park in Bārāṇasī Kingdom … and preached the dharma to five monks.” It is also stated in the Nirvana Sūtra, “The Buddha preached on the Middle Way in the Deer Park of the Bārāṇasī Kingdom. ” This indicates what sūtras were preached after the Flower Garland Sutra.

Shugo Kokka-ron, Treatise on Protecting the Nation, Writings of Nichiren Shōnin, Doctrine 1, Page 6