Warabi Kindergarten Circular Building

Introduction

Nestled in the residential streets of Warabi City in Saitama Prefecture, the Warabi Kindergarten Circular Building (わらび幼稚園円形園舎) stands as a remarkable example of mid-20th-century modernist architecture in Japan. Completed in 1963, this distinctive reinforced concrete structure was designed by Sakamoto Kanao (1911–1987), an architect renowned for his lifelong devotion to circular architecture. The building continues to serve as an active kindergarten to this day, making it a living piece of architectural heritage where children learn and play within the embrace of its curved walls.

In December 2024, the Warabi Kindergarten Circular Building was officially registered as a National Registered Tangible Cultural Property — the first building in Warabi City ever to receive this designation. This recognition acknowledges the building's architectural ingenuity in making the most of a compact urban site through its innovative circular design.

Historical Background

Warabi Kindergarten was originally established in 1948, during the early postwar years when Warabi was still a town rather than a city. The kindergarten initially operated within the grounds of Chosen-in Temple. In 1962, the kindergarten relocated to its present site in the Minami-cho district. The following year, in 1963, the iconic circular building was constructed, providing the kindergarten with a purpose-built facility that was far ahead of its time in terms of design philosophy.

The architect Sakamoto Kanao was born in Tokyo in 1911 to a distinguished family — his father served as governor of Kagoshima Prefecture and mayor of Nagoya. After graduating from the Tokyo Institute of Technology with a degree in architecture, Sakamoto joined Okura Doboku (now Taisei Corporation) in 1937. Following military service during the war, he returned to the company before establishing his own architectural practice in 1954. Over the course of his career, Sakamoto designed more than 100 circular buildings throughout Japan, including schools, hospitals, and public buildings, passionately advocating for the economic efficiency and structural rationality of the circular form.

Warabi Kindergarten celebrated its 70th anniversary in 2018, and the circular building has been in continuous use for over 60 years. Today, approximately 140 children attend the kindergarten, learning and growing within this architecturally significant structure.

Why It Was Designated a Cultural Property

The Warabi Kindergarten Circular Building was registered as a National Registered Tangible Cultural Property on December 3, 2024. The Agency for Cultural Affairs evaluated the building based on the criteria set forth in the Act on Protection of Cultural Properties, which considers structures over 50 years old that contribute to the historical landscape of the nation.

The building was recognized for several distinctive qualities. Its circular floor plan represents an ingenious architectural solution for a constrained urban site, allowing natural light to reach interior spaces from multiple angles. The design by Sakamoto Kanao demonstrates his mastery of circular architecture, cleverly arranging fan-shaped nursery rooms around a central play hall on the first floor, while stepping back the second floor to create a rooftop terrace along the perimeter. This thoughtful approach to spatial design on a narrow plot earned it recognition as an exceptional example of Sakamoto's architectural philosophy applied to early childhood education facilities.

This designation marked a historic milestone for Warabi City, as it was the first building in the city to be recognized as a Registered Tangible Cultural Property.

Architectural Highlights and Points of Interest

The Warabi Kindergarten Circular Building is a two-story reinforced concrete structure with a total building area of 398 square meters. Its most striking feature is the perfectly circular floor plan, which sets it apart from conventional rectangular school buildings.

On the first floor, the entrance opens on the north side, leading into a central play hall that serves as the heart of the building. Surrounding this communal space, fan-shaped nursery rooms radiate outward like slices of a pie, each benefiting from windows along the curved exterior wall. This arrangement ensures that every classroom receives ample natural light throughout the day, regardless of its position within the circle.

The second floor is designed to be slightly smaller in diameter than the first, creating an outdoor rooftop terrace along its perimeter. This stepped-back design not only provides additional open-air play space for the children but also allows more sunlight to reach the ground level. The terrace offers a unique elevated vantage point, giving children a sense of openness that is rare in the densely built urban environment of Warabi City.

The building exemplifies the design philosophy of Sakamoto Kanao, who believed that circular structures offered superior efficiency in land use, structural integrity, and the creation of warm, communal spaces — qualities especially well-suited to a kindergarten setting. Other surviving examples of his circular architecture, such as the former Kurayoshi Municipal Meilin Elementary School in Tottori Prefecture (now the Enkei Gekijo Kurayoshi Figure Museum), have also gained recognition as significant modernist architecture in Japan.

Visitor Information

As an active kindergarten, the Warabi Kindergarten Circular Building is a functioning educational facility and is not open to the general public for interior tours. However, the exterior of the circular building can be appreciated from the surrounding streets, and architecture enthusiasts are welcome to admire the distinctive form from outside.

The kindergarten is located an approximately 11-minute walk from the west exit of JR Nishi-Kawaguchi Station on the Keihin-Tohoku Line. The surrounding neighborhood is a quiet residential area that offers a pleasant walking environment. Visitors interested in the building are encouraged to be respectful of the kindergarten's operations and the privacy of the children and staff.

Warabi City itself is one of the smallest municipalities in Japan by area, making it easy to combine a visit to the kindergarten building with other local cultural attractions on foot or by short transit rides.

Surrounding Attractions

Warabi City, historically known as a post town on the Nakasendo highway and a center of textile weaving, offers several cultural sites within easy reach of the kindergarten.

Sangaku-in Temple — One of the most prominent temples in the area, Sangaku-in (formally known as Konkisan Gokurakuji Sangaku-in) is a Shingon Buddhist temple that received vermilion seal letters from Tokugawa Ieyasu in 1591 and continued under the patronage of successive Tokugawa shoguns. The temple features a grand main hall, a three-story pagoda, and an Amida hall, along with a collection of cultural properties including stone monuments and Buddhist statuary.

Warabi Castle Ruins Park — The site of Warabi Castle, built during the Nanbokucho period by the Shibukawa clan, is now a peaceful city park. The park also houses the Monument to the Birthplace of the Coming-of-Age Ceremony, commemorating the fact that Warabi held Japan's first modern coming-of-age ceremony in 1946.

Warabi Historical Museum — This free museum presents the history of Warabi as a Nakasendo post town, with reconstructions of the honjin (official inn) interior, merchant houses, and displays of traditional weaving tools. Adjacent to the museum is the restored Warabi Honjin, a designated cultural property of the city.

Wakarabi Shrine — Located next to Warabi Castle Ruins Park, this Shinto shrine was established in the Meiji period by consolidating eight village shrines. It hosts various seasonal festivals and provides a tranquil green space amid the urban landscape.

Kawanabe Kyosai Memorial Museum — Dedicated to the Edo-period painter Kawanabe Kyosai (1831–1889), known for his bold and humorous works, this small museum offers rotating exhibitions of his paintings and drawings.