Built in the Arai Family Home

Arai Family Residence Inner Storehouse (Uchigura): An Edo-Period Gem in Tokyo's Musashino Landscape

Tucked away in the quiet residential neighborhood of Iruma-chō in Chofu City, western Tokyo, the Arai Family Residence Inner Storehouse (新井家住宅内蔵, Arai-ke Jūtaku Uchigura) stands as a remarkable survivor of traditional Musashino farmstead architecture. Registered as a national tangible cultural property in April 2014, this earthen storehouse dates from the late Edo period (circa 1830–1868) and forms part of a larger historic compound that includes a thatched-roof main house, an outer storehouse, a former silkworm-raising room, and a traditional middle gate with walls.

In an era when Tokyo's rapid urbanization has erased much of its rural heritage, the Arai family compound remains an extraordinary pocket of living history — a place where the atmosphere of a prosperous Musashino farming household endures amid the surrounding residential streets of modern Chofu.

What Is a Kura? Understanding the Inner Storehouse

The Japanese kura (蔵) is a traditional storehouse constructed with thick earthen walls designed to protect valuable possessions from fire, theft, and the elements. Kura are broadly categorized into two types based on their position within a farmstead compound: the soto-gura (外蔵, outer storehouse), typically used for storing grain and agricultural produce, and the uchi-gura (内蔵, inner storehouse), positioned closer to the main dwelling and reserved for the family's most precious belongings — documents, ceremonial items, heirloom textiles, and other treasured goods.

The Arai Family Residence Inner Storehouse exemplifies this uchi-gura tradition. Situated within the compound grounds close to the main house, it reflects the family's status as an established farming household in the Musashino region. The building features the characteristic dozo-zukuri (土蔵造) construction method, with thick walls of layered earth and plaster that provide excellent fire resistance and climate control — essential qualities for preserving important family possessions across generations.

Why Was It Designated a Cultural Property?

The Arai Family Residence Inner Storehouse was registered as a national tangible cultural property (登録有形文化財) on April 25, 2014, under the criterion of contributing to the historic landscape of the nation. This registration recognized its significance on several levels.

First, the storehouse is a rare surviving example of Edo-period dozo construction within the Tokyo metropolitan area. While such storehouses were once commonplace throughout the Musashino region, urbanization and wartime destruction have claimed the vast majority. The Arai compound's survival, with its ensemble of main house, inner storehouse, outer storehouse, former silkworm room, and gate, offers an exceptionally complete picture of a traditional Musashino farmstead.

Second, the inner storehouse contributes to a broader historic landscape. Together with the estate woodland (屋敷林, yashiki-rin) that surrounds the compound, the buildings preserve the spatial character of a pre-modern rural settlement on the Musashino Plateau — a landscape type that has become exceedingly rare in metropolitan Tokyo.

Third, the compound as a whole documents the social and economic history of the region. The presence of both an inner storehouse for valuables and an outer storehouse for grain, along with a former silkworm-raising facility from the Meiji era, speaks to the diversified agricultural economy that sustained Musashino farming families through centuries of change.

Architectural Highlights and Points of Interest

The inner storehouse showcases the traditional dozo-zukuri construction that was the hallmark of Japanese storehouse architecture. Its thick earthen walls, typically built up in multiple layers of clay mixed with straw and finished with a smooth white plaster surface, were engineered to resist fire — a constant threat in Edo-period Japan. The distinctive hachimaki (鉢巻), a projecting band of plaster running around the exterior walls, serves both a decorative and a practical function by shedding rainwater away from the wall surface.

Visitors to the neighborhood can also appreciate the broader Arai compound. The main house (主屋) is a single-story wooden structure with a hipped thatched roof, currently protected by a temporary metal covering. With a building area of 128 square meters, it features a traditional layout with an earthen-floor work area (doma) on one side and a series of tatami rooms including a reception hall (hiroma), middle room (nakanoma), tea room (chanoma), sleeping quarters (heya), and inner chamber (okunoma). This layout is characteristic of prosperous Musashino farmhouses of the late Edo period.

The outer storehouse (外蔵), dating from the Meiji era (1883–1897), is a two-story dozo structure of 35 square meters with a gable roof and mortar-finished exterior walls. A family crest or trade mark is displayed on the eastern gable end. Nearby, the former silkworm-raising room (旧蚕室) stands as a tangible reminder of the sericulture industry that brought prosperity to many Musashino farming families during the Meiji period. Though its interior was modified after the war, the original roof framing structure remains intact.

The entire compound is embraced by a lush estate woodland — a traditional feature of Musashino farmsteads that once served as a windbreak, a source of fuel and compost, and a defining element of the regional landscape. Walking along the perimeter, one can sense the quiet dignity that characterizes old farming estates in the western Tokyo suburbs.

The Musashino Farmstead Tradition

To fully appreciate the Arai compound, it helps to understand the Musashino region's distinctive agricultural heritage. The Musashino Plateau, a broad volcanic ash tableland stretching across western Tokyo and southern Saitama, was extensively developed for farming during the Edo period. Unlike the rice paddies of lowland Japan, Musashino farms primarily cultivated dry-field crops such as wheat, millet, and vegetables on the nutrient-poor Kanto loam soil.

Farmsteads in this region developed a characteristic spatial pattern: a main dwelling surrounded by estate woodland, with storehouses, work buildings, and agricultural land arranged around a central yard. Prosperous families like the Arai maintained multiple storehouses to separate valuable family possessions from agricultural stores — a practice reflected in the distinction between the inner and outer kura at this compound.

The addition of a silkworm-raising room during the Meiji period reflects a broader economic shift. As Japan modernized and opened to international trade after 1868, silk became one of the nation's most important export commodities, and many Musashino farming families supplemented their income with sericulture. The Arai family's former silkworm room is one of the few surviving examples of this once-widespread practice in the Tokyo suburbs.

Visiting Information and Access

The Arai Family Residence is a private property and is not regularly open to public viewing. However, the exterior of the compound and its surrounding estate woodland can be appreciated from the public road. During the annual Tokyo Cultural Property Week (東京文化財ウィーク), typically held in late October to early November, some registered cultural properties in the city may offer special limited openings — visitors are encouraged to check with the Chofu City Board of Education or the city's cultural affairs section for current event information.

The compound is located in the Iruma-chō district of Chofu City, a leafy residential area near the border with Komae City and close to the Nogawa River. The nearest station is Narita on the Odakyu Line, from which the site is approximately a 20-minute walk. Alternatively, Sengawa Station on the Keio Line is about 25 minutes on foot. Local community buses also serve the area.

Nearby Attractions and Surroundings

The Iruma-chō area offers several points of interest for visitors exploring Chofu's cultural landscape. The Jindai Botanical Garden (神代植物公園), one of Tokyo's finest public gardens, is located roughly 2 kilometers to the north and features extensive rose gardens, seasonal flower displays, and a tranquil woodland setting. Adjacent to the botanical garden, the ancient Jindai-ji Temple (深大寺) is one of the oldest Buddhist temples in the Tokyo area, famous for its atmospheric grounds and the local specialty of hand-made soba noodles served at numerous restaurants in the temple's approach.

For enthusiasts of traditional architecture, the Maki Family Residence (真木家住宅), another registered tangible cultural property in Chofu's Kamiishiwara district, features both a Japanese-style main building and a Western-style wing dating from the early modern period. The former Mushanokōji Saneatsu Residence (旧武者小路実篤邸) in Chofu's Wakaba-chō, registered as a national tangible cultural property in 2018, offers a glimpse into the life of one of Japan's celebrated modern literary figures, set within the peaceful Saneatsu Park.

Nature lovers will enjoy walking along the Nogawa River (野川), a gentle stream that flows through the area and provides a pleasant greenway for cycling and strolling. The nearby Musashino-no-Mori Park (武蔵野の森公園) offers expansive green spaces with views of the surrounding landscape.