Nagusa Megaliths

Ashikaga is a historic city blessed with abundant nature and many well-preserved temples and shrines. While there is plenty to see in the city center, a short trip to the outskirts reveals cultural properties of a different kind. The Nagusa Megaliths are one such site. Located upstream on the Nagusa River, where fireflies live, this mysterious scenic area has long been revered as an iwakura, a sacred rock formation believed to house deities.

The megaliths are believed to have originally formed from a body of granitic magma about 0.9 miles in diameter that cooled and solidified during the Cretaceous Period. Rare even in Japan, they display a weathering process characteristic of granite known as “onion-skin weathering.” Their formation is also considered academically significant, and the site was designated a National Natural Monument in 1939.

The main highlights are the Offering Stone, the largest of the megaliths, and Itsukushima Shrine, which stands atop the giant rocks. According to tradition, the shrine originated when Kōbō Daishi enshrined Benzaiten here during the early Heian period, in the Kōnin era (810–824). The Offering Stone stands about 36 feet high and measures approximately 98 feet around. Even the triangular capstone on top, which looks small at first glance, is about 10 feet high. Passing through a gap in the Offering Stone is known as tainai-kuguri, or “womb passage.” It is believed to bring blessings of fertility and safe childbirth.

Another notable formation is Benkei’s Hand-Split Stone, which is split cleanly down the middle. Its name comes from the legend that the warrior monk Benkei stood firmly atop it and split the rock in two.
Today, the shrine is cherished by local residents as one of the temples and shrines on the Ashikaga Seven Lucky Gods Pilgrimage. Be sure to stop by for a visit.