Seventy five metres of straight line
The Former Chuo Line Tamano Fourth Tunnel (旧中央線玉野第四隧道, Kyu-Chuosen Tamano Daiyon Zuido) is a brick railway tunnel in Tamano-cho, Kasugai City, Aichi Prefecture, built in 1900 (Meiji 33) and listed as a Registered Tangible Cultural Property in 2016.
It measures 75 metres long and 4.6 metres wide, and it was bored dead straight. Stand at one portal and the far end appears as a single disc of daylight, which is not something a curved tunnel will give you. Walkers on the old trackbed tend to stop here first. Locally the bore is called Tunnel No. 4, and it lies about 400 metres towards Tajimi from the Former Chuo Line Tamano Third Tunnel.
The section is the horseshoe profile used for single track. Construction of the railway between Nagoya and Tajimi began in November 1896 and the line opened on 25 July 1900. Fourteen tunnels were driven along the ten kilometres or so between Kozoji and Tajimi, and thirteen of them still stand. When postwar traffic outgrew a single track, a double tracked and electrified route was cut on a new alignment, and the old line closed in 1966.
A coping stone, and the idea that a portal is architecture
Kasugai City's registration notice gives two reasons for listing the Former Chuo Line Tamano Fourth Tunnel: it is a brick tunnel, and its brick portal carries stone decoration including a coping stone across the upper part. The criterion applied was the third of the three available, covering structures that would not be easy to reproduce.
A coping stone is the horizontal capping laid along the top of a wall. Its practical job is to throw rainwater clear of the face below. Its other job is to draw one firm line across the composition and declare where the wall ends. On a portal of red brick, that grey line does a great deal of work. The Agency for Cultural Affairs describes the portal as brick built with dressed stone used at key points such as the coping, and calls the tunnel a fine example of a government railway bore.
Deciding where to spend stone was a question of money set against appearance. Build the whole face in masonry and you get strength and dignity at high cost. Use cut stone only where the eye lands and the outline tightens for far less. This portal took the second path, and it is worth standing back far enough to see the whole face before walking through.
Stretcher bond walls and niches for the living
Inside, the side walls show their bricks laid long face outwards in continuous horizontal courses, a pattern called stretcher bond. The Agency for Cultural Affairs records exactly this for the lining of the Former Chuo Line Tamano Fourth Tunnel. Because the joints run in fine level lines, the wall reads as smoother than it is. Higher up the bond changes and the bricks turn to form the ring of the arch.
Shallow niches are cut into the side walls at intervals. These refuge recesses were the only escape a track worker had in a single bore when a train came through. They hold one person, barely. Stepping into one tells you more about Meiji railway labour than any caption could.
No two portals in this group of tunnels repeat a design, according to the committee that looks after them, so the coping stone here was part of giving Tunnel No. 4 a face distinct from its neighbour. The same committee notes that after roughly half a century with no human attention at all, almost no brick has fallen from these linings.
Forty years under the scrub
The Former Chuo Line Tamano Fourth Tunnel spent a long time out of sight. Rails and sleepers went soon after closure, bamboo and undergrowth took the formation, and even in the neighbouring villages few people could have pointed to a portal.
Recovery began by accident in 2005, when JR's Katsukawa Station was rebuilt on a viaduct and its red brick platform base, in place since the Meiji era, was due for demolition. A campaign to reuse those bricks in local regeneration prompted an elderly resident to mention that there had once been brick tunnels near Jokoji Station. The search that followed took months of pushing through scrub before anyone reached a portal.
Volunteer survey work started in 2007, and the Aigi Tunnel Group Preservation and Regeneration Committee was constituted as a non profit organisation in August 2009. That February, four bores including this one had already been recognised by the Ministry of Economy, Trade and Industry as modern industrial heritage. In June 2014 a national trust campaign backed by more than 11,000 donors secured 160,000 square metres of land on the Aichi side. Registration as cultural property followed with the gazette notice of 29 November 2016, covering three structures at once: this tunnel, the Tamano Third Tunnel and the Kasaishihora Culvert. They were the first cultural properties registered in Kasugai City.
Getting in, and walking it
The trackbed holding the Former Chuo Line Tamano Fourth Tunnel is gated and locked outside the two annual openings and occasional on site events. The openings are run by the owner, the preservation committee, together with the Kasugai City Tourism and Convention Association. The 2026 autumn opening is announced for 28 November to 6 December, nine days.
At recent openings admission was 100 yen per person on the day, free for children of primary school age and under, no booking needed. Gates 9:30 to 15:00, last entry 14:00, cancelled in rain. The open route runs about 1.7 kilometres and takes in Tunnels No. 3 to No. 6, so 3.4 kilometres for the round trip and about two hours at a walking pace. Tunnel No. 4 is the second bore you pass after the entrance. Fees and hours are reset for each opening, so confirm on the committee's site before you travel.
The original ballast is still down and it shifts underfoot, so wear shoes with a firm sole. The organisers ask visitors to carry a torch. Pets are not allowed. No photography restriction has been published and visitors' pictures circulate on the committee's own social media, but follow signage and stewards on the day.
Jokoji Station on the JR Chuo Line is the access point, a little over half an hour from Nagoya on a local train, with some rapid services calling during opening periods. From the station take the small path below the platform upstream for about 300 metres, five minutes on foot. The station is unstaffed, so carry a return ticket or an IC card, and note that there is no parking either at the site or near the station.
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Q&A
- Can I go inside the Former Chuo Line Tamano Fourth Tunnel?
- Yes, but only during the spring and autumn special openings, or at occasional events. The site is locked the rest of the year. At recent openings entry cost 100 yen per person, free for children of primary school age and under, with no booking. Gates ran 9:30 to 15:00, last entry 14:00. The 2026 autumn opening is announced for 28 November to 6 December.
- Where is the Former Chuo Line Tamano Fourth Tunnel, and how far is it from Tunnel No. 3?
- It stands on the abandoned Chuo Line formation in Tamano-cho, Kasugai City, about 400 metres towards Tajimi from the Tamano Third Tunnel. The nearest station is Jokoji on the JR Chuo Line, about five minutes on foot from the reception point 300 metres upstream of the platform.
- What are the dimensions and construction of the Tamano Fourth Tunnel?
- Brick, 75 metres long and 4.6 metres wide, with the horseshoe section standard for single track. The side walls of the lining are laid in stretcher bond, refuge recesses are cut into them, and the brick portal uses dressed stone at key points including the coping.
- Why was the Tamano Fourth Tunnel registered as a cultural property?
- It was registered under the criterion covering structures that would not be easy to reproduce. Kasugai City cites the brick construction of the bore and the stone decoration, including the coping stone, on the upper part of the brick portal. The gazette notice took effect on 29 November 2016.
- What should I bring to walk the Tamano Fourth Tunnel and the old line?
- Shoes with a firm sole and a torch. Loose ballast from the working railway still covers the formation, and lighting inside the bores is limited. The round trip is 3.4 kilometres and takes about two hours. Pets are not admitted, and since there is no parking you should come by train.
Basic Information
| Name | Former Chuo Line Tamano Fourth Tunnel (旧中央線玉野第四隧道) |
|---|---|
| Location | 1667-1 Higashitani, Tamano-cho, Kasugai City, Aichi Prefecture, and other locations |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2016 (Heisei 28) |
| Quantity | 1 unit |
| Dimensions | Length 75 metres, width 4.6 metres |
| Owner | Aigi Tunnel Group Preservation and Regeneration Committee (NPO) |
| Public Access | Open only during the spring and autumn special openings; locked and closed at other times |
References
- Agency for Cultural Affairs, National Cultural Properties Database: Former Chuo Line Tamano Fourth Tunnel
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00011316
- Kasugai City: Notice of registration as Registered Tangible Cultural Properties (structures)
- https://www.city.kasugai.lg.jp/bunka/bunkazai/shinai/1004355.html
- Aichi Prefecture: Announcement of registered tangible cultural properties (structures)
- https://www.pref.aichi.jp/soshiki/bunkazai/tourokubunnkazaikennzoubutu.html
- Aigi Tunnel Group Preservation and Regeneration Committee: about the Aigi Tunnels
- https://aigi-tunnel.org/about_tunnel.html
- Aigi Tunnel Group Preservation and Regeneration Committee: modern industrial heritage and registered cultural properties
- https://aigi-tunnel.org/bunkazai-kinsan.html
- Aigi Tunnel Group Preservation and Regeneration Committee: report on the 36th spring opening, with visiting details
- https://aigi-tunnel.org/News/2026/2026Haru-houkoku.html
Last verified: 2026.08.31