The Shape and Structure of Hachizuka Kofun
A Large Circular Burial Mound
Hachizuka Kofun stands on the edge of a hill extending from Mount Satsukiyama, on the eastern side of the Inagawa River in northern Osaka. The mound is now understood to be a large circular kofun approximately 45 meters in diameter. Earlier interpretations classified it as a different type of burial mound, but archaeological research has provided stronger evidence for its circular form.
The mound was constructed in two tiers and was surrounded by a moat approximately 7 meters wide and 0.8 meters deep. Including the surrounding moat, the site had an overall diameter of approximately 62 meters.
The name Hachizuka has two traditional explanations. One theory connects it with the mound’s appearance, which is said to resemble an overturned bowl, while another suggests that a bowl was discovered inside the stone chamber.
An Exceptionally Large Stone Burial Chamber
A Corridor-Style Stone Chamber
The burial facility is a side-entry stone chamber with chambers extending from both sides of the central passage, known in Japanese archaeology as a ryosode-shiki yokoguchi-shiki sekishitsu. The entrance faces south.
The chamber is constructed from several types of stone, including granite, chert, and slate. The careful arrangement of these materials demonstrates the considerable engineering skill involved in constructing such a monumental tomb more than 1,400 years ago.
Dimensions of the Stone Chamber
The entire stone chamber measures approximately 14.88 meters in length. The burial chamber itself is about 6.48 meters long, 3.2 meters wide, and 5.2 meters high.
The entrance passage measures approximately 8.40 meters long, with an average width of 1.8 meters and an average height of about 2 meters.
Three large ceiling stones cover the main burial chamber, while four cover the entrance passage. With a height of 5.2 meters, the chamber is among the largest and tallest of its kind in Osaka Prefecture, giving visitors a sense of the impressive scale of the original tomb.
From an Ancient Tomb to a Medieval Sacred Site
Later Buddhist Monuments
Hachizuka Kofun continued to have significance long after the original burial. During the medieval period, Buddhist monuments including a thirteen-story stone pagoda, stone memorial monuments, and Buddhist statues were placed within the ancient stone chamber.
A sutra mound, or kyozuka, was also created on top of the kofun. This practice involved burying Buddhist scriptures or related objects as a religious act, adding another historical layer to the site.
The continued use of the ancient tomb for religious purposes illustrates how sacred landscapes in Japan could evolve over many centuries rather than being abandoned after their original function had ended.
Cultural Properties at Gosha Shrine
The Thirteen-Story Pagoda
One of the most important monuments associated with Hachizuka Kofun is the thirteen-story pagoda within the grounds of Gosha Shrine. Built during the early Muromachi period, the pagoda is designated as a National Important Cultural Property.
Its presence beside the ancient burial mound demonstrates the complex relationship between ancient burial traditions and later Buddhist religious practices. The pagoda is an important historic structure in its own right and adds considerably to the cultural significance of the site.
Artifacts from the Sutra Mound
Objects discovered from the sutra mound on the upper part of Hachizuka Kofun have also been preserved as Ikeda City cultural properties.
The sutra mound dates from the Kamakura period, and excavated objects include a lidded jar-shaped container, mirrors, bronze objects, and Song-dynasty Chinese coins. These artifacts provide valuable evidence of religious practices, material culture, and connections with the wider East Asian world during medieval Japan.
Archaeological Research
Early Investigation by William Gowland
Hachizuka Kofun has attracted scholarly attention for well over a century. In 1887, the British engineer and archaeologist William Gowland investigated the site. Gowland is well known for his pioneering research into Japanese kofun and ancient stone chambers during the Meiji period.
Further research continued in the 20th century. In 1934, archaeologist Umehara Sueji carried out detailed measurements of the stone chamber, contributing to the scholarly understanding of its structure and scale.
The 2001 Excavation
A major archaeological investigation was conducted in 2001. Excavation of the mound provided important evidence concerning its shape and led to the present understanding that Hachizuka Kofun is a circular burial mound.
Research into the mound, stone chamber, and associated artifacts continues to shed light on the people and society that existed in the Inagawa region during the transition from the Kofun period to the early medieval era.
A Long History of Preservation
The historical importance of Hachizuka Kofun has been recognized through a series of designations and archaeological investigations.
In 1959, the thirteen-story pagoda at Gosha Shrine was designated a National Important Cultural Property. In 1970, Hachizuka Kofun itself was designated an Osaka Prefecture Historic Site.
The major excavation of 2001 provided further evidence about the form of the burial mound and helped establish the current archaeological interpretation of the site.
Experience Ancient and Medieval Japan in One Place
Hachizuka Kofun offers a fascinating glimpse into the long history of the Ikeda area. Created around the end of the 6th or beginning of the 7th century, the monumental burial mound reflects the power and beliefs of local leaders during the ancient Kofun period.
Its enormous stone chamber is particularly impressive, while the later thirteen-story pagoda, Buddhist monuments, and sutra mound demonstrate how the site continued to acquire new religious significance over the centuries.
Today, protected within the grounds of Gosha Shrine, Hachizuka Kofun preserves an extraordinary combination of archaeological and religious heritage. For travelers interested in ancient Japanese history, Buddhist culture, and the evolution of sacred landscapes, it provides a rare opportunity to encounter several different periods of Japan’s past in a single historic site.