The Riki Tunnel

The Tenryu Hamanako Railway Riki Tunnel (天竜浜名湖鉄道利木隧道) is a concrete railway tunnel of 1936 on the Tenryu Hamanako Railway about 4.6 kilometres south-west of Mikkabi Station in the border area of Hamamatsu and Kosai City, Shizuoka Prefecture, and was registered as a Registered Tangible Cultural Property (structure) on January 26, 2011 (Agency for Cultural Affairs).

The Agency records a concrete tunnel 663 metres long and 4.8 metres wide; registration number 22-0145.

The Longest Tunnel on the Line

The Riki Tunnel was built for the old national Futamata Line through the inland west of Shizuoka. It is a gently curving concrete tunnel with a horseshoe-shaped section, 663 metres long, the longest on the line (Agency for Cultural Affairs).

Inside are 14 refuge niches, and the fittings that once held maintenance lamps remain (Agency for Cultural Affairs).

Why It Was Registered

It was registered under the criterion of contributing to the historic landscape of the country (Agency for Cultural Affairs). It is the line's longest tunnel and keeps the refuges and lamp fittings used by maintenance crews.

What to Look For

Look for the horseshoe-shaped bore, its gentle curve and the 14 refuge niches (Agency for Cultural Affairs).

Visiting

The tunnel runs from Shimoona in Mikkabi-cho, Hamamatsu, to Riki in Kosai City, about 4.6 kilometres south-west of Mikkabi Station (Agency for Cultural Affairs), and is in daily railway use. Tickets, fares and the turntable tour are covered on the Tenryu Hamanako Railway page. Do not enter the tracks or railway land.

The Kita Ward of Hamamatsu named in the Agency's record became part of Hamana Ward when the city reorganised its wards on January 1, 2024; town names and lot numbers did not change (Hamamatsu City).

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Q&A

QWhen was the Tenryu Hamanako Railway Riki Tunnel built?
AIn 1936 (Agency for Cultural Affairs).
QWhere is the Tenryu Hamanako Railway Riki Tunnel?
AFrom Shimoona, Mikkabi-cho, Hamamatsu, to Riki, Kosai, about 4.6 kilometres south-west of Mikkabi Station.
QWhat should I look for?
AIts 663-metre length, the longest on the line, and 14 refuges.
QCan I visit the Tenryu Hamanako Railway Riki Tunnel?
AIt is a working tunnel and cannot be entered.
QWhen was the Tenryu Hamanako Railway Riki Tunnel registered?
AOn January 26, 2011 (Agency for Cultural Affairs).

Basic Information

NameTenryu Hamanako Railway Riki Tunnel (天竜浜名湖鉄道利木隧道)
LocationShimoona, Mikkabi-cho, Kita Ward, Hamamatsu City, to Riki, Kosai City, Shizuoka Prefecture
DesignationRegistered Tangible Cultural Property (Structure)
Year DesignatedRegistered 2011/01/26 (Heisei 23)
Quantity1 structure
DimensionsConcrete, 663 m long, 4.8 m wide
OwnerTenryu Hamanako Railway Co., Ltd.
Public AccessIn railway use (no access to the structure)

References

Tenryu Hamanako Railway Riki Tunnel (Database of National Cultural Properties, Agency for Cultural Affairs)
https://kunishitei.bunka.go.jp/heritage/detail/101/00008461
Cultural Properties along the Line (Tenryu Hamanako Railway, Japanese)
https://www.tenhama.co.jp/spot/bunkazai/
Ward Reorganisation (Hamamatsu City, Japanese)
https://www.city.hamamatsu.shizuoka.jp/kikaku/kuseido/index.html

Last verified: 2026.10.14