A Center of Politics and Religion in Ancient Kozuke
Following the Taika Reform of 645, Japan underwent major political changes as the country was reorganized into a centralized state based on the Ritsuryo system of laws and administration.
The country was divided into more than 60 provinces, which were classified according to their size and importance. Kozuke was designated as a “Taikoku,” or major province, placing it among the highest-ranking provinces in the system.
The provincial government, or kokufu, was located in the area around present-day Maebashi. Government offices, residences for officials, accommodations for soldiers, markets, schools, and other facilities formed an important administrative center.
Kozuke Kokubunji was built to the northwest of this provincial government center. The monastery and convent were deliberately established near each other, making the area one of the most important political and religious centers of ancient Gunma.
Why the Kokubunji Temples Were Built
In 741, during the Nara period, Emperor Shomu ordered the construction of a provincial monastery and convent in every province of Japan.
The project was intended to promote national stability through Buddhism. The great Todaiji Temple was established in the capital as the central temple, while Kokubunji temples were constructed throughout the provinces as part of this enormous national undertaking.
Japan at the time was experiencing repeated natural disasters, epidemics, and political instability. Emperor Shomu hoped that Buddhist teachings and rituals would help protect the country and bring peace and prosperity.
The Grand Scale and Layout of Kozuke Kokubunji
A Vast Temple Precinct and Seven-Story Pagoda
The main temple precinct covered an enormous area of approximately 220 meters from east to west and 235 meters from north to south.
The grounds were surrounded by earthen walls constructed using the rammed-earth technique known as hanchiku. Gates were placed at the center of each side of the enclosure.
The principal buildings were arranged along a north-south axis, with the South Gate, Central Gate, Main Hall, and Lecture Hall aligned in sequence. A magnificent seven-story pagoda stood to the west of the Main Hall.
This type of arrangement is associated with the Todaiji-style, or Kokubunji-style, temple layout. The Main Hall housed the principal Buddhist image, while the Lecture Hall stood behind it, creating a formal and impressive temple complex.
The Seven-Story Pagoda
The seven-story pagoda is believed to have stood at a height of more than 60 meters, making it a remarkable landmark in ancient Kozuke.
The reconstructed pagoda platform measures approximately 19.2 meters on each side. Seventeen foundation stones remain arranged in an orderly pattern, demonstrating the impressive scale of the original structure.
The foundation is regarded as one of the largest surviving examples of its type in Japan and provides visitors with a tangible impression of the scale of the ancient temple.
Reconstructed Rammed-Earth Walls
As part of the preservation and restoration project, sections of the temple’s earthen walls have been reconstructed using the traditional hanchiku technique.
This method involved piling up layers of earth and repeatedly compacting them to create a strong wall. The reconstruction provides an opportunity to see how advanced civil engineering techniques were used during the Nara period.
It is particularly notable as an early full-scale reconstruction of this type in eastern Japan.
History from the Nara Period to Decline
From the Nara Period to the Heian Period
The Shoku Nihongi, an eighth-century Japanese historical chronicle, records a donation made to the temple in 749. This suggests that construction began soon after Emperor Shomu’s 741 order.
The principal buildings are believed to have been completed by around 750, making Kozuke Kokubunji one of the provincial temples whose construction progressed relatively quickly.
The Engishiki, a collection of laws and regulations completed in 927, records an allocation of 50,000 bundles of rice as financial support for the temple. This illustrates the importance attached to the temple by the central government.
Decline and Abandonment
By 1030, historical records described the temple buildings as damaged and deteriorating.
The decline may have been influenced by periods of warfare and political upheaval, including the Rebellion of Taira no Masakado in 939 and an attack on the Kozuke provincial government in 1180 by Ashikaga Toshitsuna.
By the latter half of the 14th century, the temple had lost its religious function. The former Lecture Hall site, for example, was being used as a cemetery.
Despite this decline, many of the archaeological remains survived without extensive destruction. The site was designated a National Historic Site in 1926, helping ensure its long-term preservation.
Kozuke Kokubunji Convent Ruins
Approximately 300 meters east of the monastery are the remains of Kozuke Kokubunji Convent, which served as the corresponding temple for Buddhist nuns.
The convent is estimated to have occupied an area of approximately 1.5 cho square, and the foundations of the Central Gate, Main Hall, Lecture Hall, and nuns’ quarters have been identified.
Unlike the monastery, the convent did not have a pagoda. Its layout is thought to have been modeled on temples such as Todaiji and Hokkeji.
The convent ruins were designated a National Historic Site on October 11, 2024. Further archaeological research and preservation work are expected to provide additional insight into the role of Buddhist convents in ancient Japan.
Archaeological Excavation and Preservation
Large-scale archaeological excavations and preservation projects have been carried out since the 1980s, led mainly by the Gunma Prefectural Board of Education.
The foundations of the pagoda and Lecture Hall have been reconstructed, while the Kozuke Kokubunjikan Guidance Center was established to help visitors understand the history of the site.
Artifacts unearthed during excavations, including roof tiles and ornamental ridge-end tiles, are displayed at the center. They provide clues about the architectural styles and decorative techniques used at the temple more than a thousand years ago.
Related materials can also be found at the Gunma Prefectural Museum of History and the Tokyo National Museum.
Experiencing Ancient History as a Visitor
Today, the Kozuke Kokubunji ruins have been developed as a spacious historic site where visitors can walk among the archaeological remains and imagine the appearance of the ancient temple complex.
The ruins spread across a gentle plateau on the southeastern foothills of Mount Haruna. The open landscape, seasonal scenery, and preserved archaeological features create a peaceful setting for exploring the history of ancient Japan.
Visitors can also combine their visit with the nearby Kozuke Kokubunji Temple, a later temple that carries on the name and religious heritage of the ancient site. Seeing both locations helps illustrate the continuity of the area’s history.
A Window into Japan 1,250 Years Ago
Kozuke Kokubunji Temple Ruins offer a fascinating glimpse into the political and religious world of Japan approximately 1,250 years ago.
The enormous temple precinct, reconstructed pagoda foundation, rammed-earth walls, and surrounding landscape allow visitors to imagine the scale of the provincial Buddhist temples that played an important role in the Ritsuryo state.
For travelers interested in Japanese history, archaeology, Buddhist culture, and ancient architecture, Kozuke Kokubunji is an important cultural destination in Gunma. Walking through the quiet ruins provides a unique opportunity to experience the foundations of ancient Kozuke and discover a side of Japan that predates the country’s famous medieval castles and samurai culture.