Nagusa Megaliths

These Mysterious Giant Rocks are Ashikaga’s Only National Natural Monument

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Ashikaga is a city with abundant nature where numerous historical temples and shrines remain. Besides those found in the city center, you will find cultural treasures that are a little different from the ordinary, if you head out to the suburbs. The Nagusa Megaliths are among these. Located upstream from where fireflies live along the Nagusa River is this mystical place of scenic beauty, whose rocks have been revered as a dwelling of the gods since ancient times.

It is said that these giant rocks were originally formed by a body of granitic magma that cooled during the Cretaceous Period to a diameter of about 1.5 kilometers. Rare in Japan, these megaliths show the “onion weathering” phenomenon that is characteristic of this granite. In recognition of their academic value, they were designated as Natural Monuments by the Japanese Government in 1939.

The highlight of this site is Itsukushima Shrine, built on top of two of the largest rocks. According to legend, Itsukushima Shrine was established at the beginning of the Heian Era during the Konin Period (810-824) by Kobo Daishi, the monk who brought Buddhism to Japan, to enshrine the goddess Benzaiten. Dedicated to the gods, the largest rock is about 11 meters high, with a circumference of approximately 30 meters. Although it may appear small at first glance, the triangular headstone is about 3 meters tall. By the way, if you pass though the space between these sacred stones, it is said that you are “going through the womb”. Once you come out on the other side, it is believed that you will be blessed with conception and safe childbirth.

Besides this, you’ll find a rock split right down the middle, called Benkei no Tewari Ishi, or “Hand-Warping Stone”. It is so named because it looks like the Buddhist monk Benkei stood on top of the rock, became two Nio demons, and split the rock in half.

Beloved by the locals, this shrine is now part of the Ashikaga Shichi-Fukujin, a course around shrines and temples connected to the Seven Lucky Gods of Japan. Don’t pass up the chance to come and visit it!


  • It is designated as a national natural monument.
  • During the Konin period (810-824), Kobo Daishi enshrined Benzaiten here.
  • Diving under the rock is said to grant wishes of conception and safe childbirth.
  • Itsukushima Shrine is part of the Ashikaga Shichi-Fukujin Seven Lucky Gods course.
  • The megaliths located inside Itsukushima Shrine are said to be its inner sanctuary.


  • A feature of Itsukushima Shrine is the bridge connecting to the main building

    A feature of Itsukushima Shrine is the bridge connecting to the main building

  • The view from atop the bridge

    The view from atop the bridge

  • Benkei no Tewari Ishi, a giant rock split straight down the middle

    Benkei no Tewari Ishi, a giant rock split straight down the middle


  • 陳隆義


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Name in Japanese
Postal Code
4990 Nagusa Kamicho, Ashikaga City, Tochigi
0284-41-9977 (Nagusa Community Center)
Free of charge
Never (always open)
Open year-round
1) About 35 minutes by taxi from Ashikaga Station on the JR Ryomo Line
2) About 35 minutes by taxi from Ashikagashi Station on the Tobu Isezaki Line
Official Website
Official Website (English)