By the middle of the 5th century an altar had appeared set atop a rock, with a large stone in its center, surrounded by pebbles arranged in a square conguration. Offerings of flat iron ingots that the Yamato court procured from the Korean peninsula also reflect importance of iron for Japan at that time.
From the second half of the 5th century onward, rituals were performed in the shadows of rocks. Offerings from this period include iron weapons, miniature knives and axes, and highly ornamented gilt-bronze harnesses from the Korean peninsula. A gold ring that bears a striking resemblance to those found in the royal Silla tombs and shards of Persian glass presumably brought to Japan by way of the distant Silk Road are important pieces of evidence for the active exchanges that were taking place at this time. Those who engaged in dangerous ocean voyages offered these treasures to the gods.
During this period the Sui unified the long-divided Chinese continent; the Tang then replaced the Sui.
The Yamato court sent envoys to cultivate relations with the Sui and Tang rulers.
After the Tang and Silla toppled Baekje, which had long been allied with Yamato, however, Yamato sent in troops and suffered a huge defeat by Tang-Silla allied forces in 663.
After the loss, Yamato accelerated its efforts to establish a centralized government modeled on the Tang.
In the period characterized by rituals performed in the shadows of rocks came to an end (Site 22) and partial rock-shadow rituals (Site 5), offerings shifted from items resembling burial objects found in mounded tombs to gilt-bronze miniature spinning and weaving tools, human figurines, and other objects that crafted especially for rituals
Written records of ancient rituals in Japan appear only from the 8th century onward, so the ritual sites on Okinoshima are an essential source of information about the formative stages of indigenous faith in Japan.
Rituals on Okinoshima appear to have changed with the times.
The ritual style that emerged in this period became the basis of indigenous Japanese ritual practices that still survive today.
These gilt-bronze artifacts resemble the divine treasures still in use today at Ise Shrine.
In the 8th century rituals were first performed in flat, open areas, some distance away from the group of rocks where they had been conducted unil that time.
Many votive offerings were deposited around the remains of a stone altar with a large rock at its center.
Offerings consisted mainly of a wide variety of pottery, including objects perforated with holes and steatite objects in the shapes of people, horses, and ships.
While these offerings share some common features with those associated with the new ritual style that prevailed at that time in Japan, some ritual objects are characterized by shapes and materials unique to the Munakata region. Rituals with a local flavor were performed within the new framework of the state.