Zozan Imperial Underground Headquarters, Nagano

Matsushiro, an unassuming former Samurai town in the south of the now all-encompassing Nagano City is not really known as a tourism hotspot, particularly for foreigners who rarely venture into Nagano for anything other than winter sports. However, hidden away down its little backstreets is one of the most important war relics in modern Japanese history.

The Zozan (meaning “elephant mountain”) Imperial Underground Headquarters in Matsushiro is an extensive series of cave networks hollowed out mostly by Korean forced labour towards the end of World War 2. The intent was to move the imperial family and the army headquarters here in the event of a US land invasion and the possibility of a “last stand”.

However, the Japanese government surrendered, and the tunnels were never completed. Today, you can still access a section of the tunnels. There are three networks in the area, though entry to the other two, further up the valley from the first, is prohibited. Apparently one has collapsed and the other now houses a seismic observatory.

Getting to the tunnels is quite a chore without your own transport. A bus is available from Nagano Station for 600 yen (five pounds) and takes half an hour. Times are infrequent, though. Matsushiro has a train station, but it is a small private line that by all accounts is closing next year. It runs from Ueda in the south to Suzaka, east of Nagano City.

From the bus stop you’ll need a map, although if you have enough Japanese to ask then local people will be able to direct you. There are signs, but only when you’re close and the tunnel entrance is tucked away behind a couple of quiet streets. English language maps (which include a close up map of Matsushiro which has the Zozan tunnels on it) are available for free from the tourist office at Nagano Station.

Entry to the tunnels is free. Opening times are 9 to 5 on weekdays. At the entrance is a small booth where you will be given a hard hat to wear inside. Next to the entrance is a memorial (tri-lingual) to the some 1500 Korean slave laborers who died during the construction of the tunnels.

The entrance to the tunnels looks similar to a mine entrance, gradually sloping down under the mountain. You go down an incline for a while before you get into the tunnels proper.

I’ve lived in Nagano for seven years, and the first time I visited the Zozan tunnels I was expecting a James Bond-style underground army base. In actual fact there’s very little to see. The tunnels have been cut in a grid pattern, although you can only walk down the central tunnel for 500m or so, while all the side tunnels branching off are fenced off. The tunnels are bare rock, and contain pretty much nothing of interest other than a few characters scrawled on the walls, apparently by some of the workers. It’s more the intent of the place and the creepy atmosphere that is fascinating for the visitor, because the complex was unfinished and therefore is just an empty network of tunnels. There are a few Japanese language signs (obviously useless to most foreign visitors) but not much else. The size of the tunnels, which tower overhead and are wide enough for a truck to drive down, is staggering, though.

The Zozan is not a busy place, and there are sometimes staff at the entrance who will offer to give you a guided tour (for free) or alternatively it is possible to arrange an English speaking guide (you will have to go to the International Centre in Nagano City, probably a few days in advance).

Nagano, apparently ashamed of its association with the war, left the Zozan tunnels off a list of sights of interest for tourists visiting for the 1998 Winter Olympics, and even today it’s not openly advertised. I heard about it from my first boss in Nagano, who no doubt heard about it from his. Unlike other local attractions like the zoo, the wild monkey park and various museums, you certainly won't see it advertised on the local trains.

In truth, though, unless you’re a serious WW2 buff or find yourself in Nagano for an afternoon with time to kill, it’s not worth making a special trip to visit, particularly not from elsewhere in Japan. If you do want to though, you can take an Asama Shinkansen from Tokyo or Ueno Stations direct to Nagano. It costs 7200 yen (60 quid) for an unreserved seat and takes around 1hour 45min. Trains leave about every half an hour.

I'd recommend it if you're visiting Nagano for other reasons (I'll be taking my father there when he visits in November) but not for a special journey.

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