Momoyama Water Metering Room

Introduction

Perched on a hillside overlooking the city of Ube in Yamaguchi Prefecture, the Momoyama Water Distribution Metering Room — affectionately known as "Rokkakudō" (Hexagonal Hall) — stands as a charming relic of Japan's Taishō-era industrial heritage. Built in 1924, this small octagonal brick building once served as the nerve center of Ube's early water supply system, measuring the flow of water destined for the growing city below. Today, it is a Registered Tangible Cultural Property of Japan and a designated Heritage of Industrial Modernization, treasured by locals and admired by visitors for its elegant Gothic-style architecture and the panoramic views of Ube's cityscape that surround it.

Historical Background

The story of the Momoyama Metering Room is inseparable from the rise of the Okinoyama Coal Mine, one of the driving forces behind Ube's transformation from a quiet village into a thriving industrial town during the Taishō period (1912–1926). As the coal mining industry expanded rapidly, Ube's population surged, and the need for a modern water supply became urgent.

The Okinoyama Coal Mine took the initiative to construct its own waterworks, drawing water from the Kotō River upstream, purifying it at the Nakayama Water Treatment Plant, and pumping it up to a reservoir on Momoyama Hill at an elevation of approximately 66 meters. From this hilltop reservoir, water was distributed to the city below using a gravity-fed system — a remarkably efficient method that relied on natural water pressure rather than mechanical pumps. The metering room was completed in December 1924 as part of this infrastructure, housing instruments to measure the volume of water flowing through two 400-millimeter mains and one 350-millimeter main before distribution.

In 1926, the entire water supply system was transferred to the City of Ube, marking a pivotal moment in the modernization of public utilities in the region. The metering room continued to serve its original purpose for decades, and even today, its presence on the hilltop stands as a testament to the foresight of early 20th-century engineers who combined functional design with aesthetic beauty.

Why It Was Designated as a Cultural Property

The Momoyama Water Distribution Metering Room was registered as a Tangible Cultural Property of Japan on November 5, 1997, under the revised Cultural Properties Protection Act. This registration system was introduced in 1996 to protect historically significant structures — particularly buildings, bridges, and civil engineering works — that might not qualify as formally designated cultural properties but nonetheless contribute to Japan's historical landscape and are difficult to replicate.

The metering room met the criteria on several grounds. It is over a century old, making it one of the oldest surviving water supply structures in Ube. Its Gothic-style architectural design, featuring a striking contrast between rectilinear pilasters and gently arched window openings, represents a style that was fashionable in early 20th-century Japanese infrastructure but is increasingly rare. The building is a tangible symbol of Ube's modernization, closely tied to the coal mining industry that shaped the city's identity.

In 2007, the metering room received further recognition when it was certified as a Heritage of Industrial Modernization by the Ministry of Economy, Trade and Industry, alongside the nearby Former Momoyama No. 1 Reservoir Surveillance Gallery Entrance. Together, these structures represent the most historically significant water supply facilities in Ube.

Architectural Highlights and Points of Interest

Despite its modest size — a single-story brick structure with a floor area of approximately 30 square meters — the Momoyama Metering Room possesses a distinctive architectural presence. The building has an octagonal floor plan with a diameter of 5.7 meters, constructed of the distinctive pink-hued bricks that are a hallmark of Ube's industrial heritage. Its Gothic-inspired design features straight, columnar pilasters along the exterior walls, contrasted with softly curved arched openings for the entrance and windows, creating a visual interplay between rigidity and grace.

When originally constructed, the building was crowned with an octagonal pyramidal roof that gave it the appearance of a small medieval castle or tower. Although the original roof was lost over time, it was faithfully restored in 2002 with a reinforced concrete flat roof, preserving the building's silhouette in the cityscape. Curiously, despite being an octagon, the building has long been called "Rokkakudō" — literally "Hexagonal Hall" — by local residents. This endearing misnomer has become part of the building's identity, and even longtime residents are sometimes surprised to learn that it actually has eight sides.

The hilltop location offers splendid views over Ube's urban center and the Suō-nada Sea beyond, making the walk up to the metering room a rewarding experience in itself. The building sits within a quiet residential neighborhood on the hillside, accessible via narrow lanes that wind upward through the community — an experience that feels like stepping back in time.

Visitor Information

The Momoyama Water Distribution Metering Room is accessible 24 hours a day for exterior viewing. The building is located in a residential area on a hillside in Ube's Nishi-Momoyama district. While the interior is not generally open to the public, the exterior and surrounding area can be freely explored at any time.

Approximately 400 meters up the hill from the metering room stands the Former Momoyama No. 1 Reservoir Surveillance Gallery Entrance, another Registered Tangible Cultural Property featuring Gothic-style decoration with pointed arches and ornamental column capitals. Adjacent to this is the Momoyama No. 3 Reservoir, completed in the late 1980s, which features a panoramic observation tower that is open to the public on weekends and holidays, offering sweeping views of the city, the Seto Inland Sea, and on clear days, the mountains of Kyushu and Shikoku. Admission to the observation tower is free.

Parking is available near the Former Momoyama No. 1 Reservoir Surveillance Gallery Entrance and the No. 3 Reservoir. From there, visitors can walk down the hill to the metering room, enjoying the residential streetscape and city views along the way.

Surrounding Attractions

Ube offers a wealth of experiences for visitors interested in industrial heritage and beyond. Tokiwa Park, one of the city's premier destinations, spans approximately 100 hectares around Lake Tokiwa and features the Coal Memorial Museum — Japan's first museum dedicated to the coal industry — with free admission, a recreated underground mine tunnel, and an observation tower built from the steel of an actual mine shaft headframe. The park is also home to Tokiwa Zoo, a botanical garden, an amusement park, and the UBE Biennale sculpture exhibition, one of the world's longest-running outdoor sculpture competitions.

For those interested in the broader story of Ube's coal mining heritage, the Okinoyama Electric Tramway Shaft Stone Wall — another Registered Tangible Cultural Property — offers a glimpse into the mining infrastructure that once powered the city's economy. The city's network of public art installations scattered throughout the urban center provides a pleasant walking experience that connects Ube's industrial past with its creative present.