Registered Tangible Cultural Properties · Kumamoto

Kumagawa Railway Iwashimizu Arch Bridge

Kumagawa Railway Iwashimizu Arch Bridge: A 1923 Five-Centred Arch

A 1923 concrete arch in Hitoyoshi carrying a stream 43 metres through the railway embankment, its portal a five-centred arch to design No. 1007, and dry-stone walls.

Designation Registered Tangible Cultural Properties

Location Kumamoto

A Small Arch Under the Embankment

The Kumagawa Railway Iwashimizu Arch Bridge (くま川鉄道岩清水アーチ橋) is a concrete arch in Ganjojimachi, Hitoyoshi City, Kumamoto Prefecture, completed in 1923 and registered as a Registered Tangible Cultural Property on 19 December 2014. It lies about 2 kilometres east of the Daiogawa Bridge, in the same district as Sagarahan-Ganjoji Station.

Do not expect a span over a river. The structure runs through the base of the railway embankment, carrying a stream from one side to the other, and its axis is 43 metres long. That is why the registration gives it a length of 3.7 metres and a width of 43 metres: the numbers follow the track, not the water.

A Five-Centred Arch

The span of the Kumagawa Railway Iwashimizu Arch Bridge is 6 feet. Its profile follows circular No. 1007, a standard design that joins arcs drawn from five centres into a shape close to a parabola. Compared with a semicircle, it rises more steeply to a slightly pointed crown, which suits the weight of earth above.

The portals are finished in mortar, flanked by wing walls of dry-laid stone, fitted without mortar so water drains freely through the joints. The structure was registered as difficult to reproduce.

The same five-centred No. 1007 arch appears at the Hirahara Arch Bridge in Taragi. There the width is 8.1 metres; here the bigger embankment turns the arch into a tunnel more than five times as long.

What to Look For

Focus on the outline of the portal. Face it squarely and you see the five-centred shape: slightly drawn in at the springing, rising to a gentle point. Inside, the 43-metre bore narrows to a small spot of daylight at the far end.

After rain the joints of the stone wing walls stand out sharply. Note the pairing of smooth mortared portal and rough dry stone.

Visiting

The Kumagawa Railway Iwashimizu Arch Bridge is part of a working line, and the track and embankment are off limits. You view the portal from nearby; the stream bank can be slippery. There is no charge. The nearest station is Sagarahan-Ganjoji, 190 yen from Hitoyoshi Onsen for adults.

No specific restriction on photography from public roads has been announced, but stay out of fields, private land and the watercourse itself.

📍 Plan Your Visit to Kumamoto: Find tours, activities & transport passes near Kumagawa Railway Iwashimizu Arch Bridge; [ Kumamoto Castle & Mt. Aso Volcano Tours ]

Q&A

QWhere is the Kumagawa Railway Iwashimizu Arch Bridge and what is the nearest station?: AIt is in Kamaya, Ganjojimachi, Hitoyoshi City, about 2 kilometres east of the Daiogawa Bridge. The nearest station is Sagarahan-Ganjoji.

QWhat kind of structure is the Kumagawa Railway Iwashimizu Arch Bridge?: AA concrete arch that carries a stream through the base of the railway embankment, with a 6-foot span and an axis 43 metres long.

QWhat should I look for at the Kumagawa Railway Iwashimizu Arch Bridge?: AThe five-centred, near-parabolic arch of the portal, built to standard design No. 1007, and the dry-laid stone wing walls.

QCan visitors see the Kumagawa Railway Iwashimizu Arch Bridge?: AThe portal can be viewed from nearby at no charge. The track and embankment are closed to the public.

QCan I take photographs of the Kumagawa Railway Iwashimizu Arch Bridge?: ANo specific restriction on photography from public roads and other permitted places has been announced. Do not enter the track, fields or private land. Commercial filming and press coverage go through the Kumagawa Railway's filming and coverage request page.

Basic Information

Name	Kumagawa Railway Iwashimizu Arch Bridge (くま川鉄道岩清水アーチ橋)
Location	Kamaya, Ganjojimachi, Hitoyoshi City, Kumamoto Prefecture
Designation	Registered Tangible Cultural Property (structure), registration No. 43-0132
Year Designated	Registered 2014/12/19 (Heisei 26)
Quantity	1 structure
Dimensions	Concrete single-arch bridge, 3.7 metres long, 43 metres wide, with wing walls
Owner	Kumagawa Railway Co., Ltd.
Public Access	In railway service; no access to the track or embankment, the arch portals can be viewed from nearby