The Ōtama Trail, Oku-Tama, Tokyo: Up the Tama River

The return of spring to Japan brings ideal conditions for exploring the mountains and forests. Being several kinds of tired lately (one reason this blog has been slow of late), I started with a very straightforward back-to-basics route in Oku-Tama (奥多摩).

This is an easy and accessible walk, only three to four hours long, with a few gentle ups and downs but nothing really strenuous. It follows the upstream Tama river (Tamagawa, 多摩川), snaking up the beautiful Hatonosu Valley and Kazuma Gorge over bridges, sleepy village lanes and woodland trails. Refreshing views and the sound of flowing water are a constant for most of the way, and unique highlights include a dam with a special “fish passage”, some charming local cafés, and Oku-Tama's celebrated fresh wasabi.

A few of my previous Oku-Tama mountain walks have featured in this blog, such as Mitake-san/Ōdake-san, Takamizu Sanzan and the more serious Takanosu-yama (two others, Kawanori-yama and Gozen-yama, I am saving for my hiking guidebook). But today's route stays in the valley, paralleling the far end of the Ōme Line across its last four stations. As such, it gives you more exposure to the human side of Oku-Tama, to which it offers an excellent introduction for first-timers in the area.

Oku-Tama (yellow, far left) within Tokyo metropolis. Central Tokyo is the purple area on the right.

It may come as a surprise that Oku-Tama is part of Tokyo at all. Although the metropolis's largest subdivision, only about 6,500 people live in it, mostly concentrated into little villages or towns amidst its expansive mountains and forests. Despite its contrast with the world of concrete further east, the two have been connected for quite some time: typically hikers, fishers, campers and pilgrims have come one way, while timber, limestone, drinking water and hydroelectric power have gone the other.


As its name suggests, Oku-Tama's defining feature and chief artery is the Tama river, whose upper reaches from Oku-Tama Lake (奥多摩湖) are narrow, energetic and occasionally angry, in contrast to its broader and more silently intent downstream sections. Anyone based around the south of Tokyo will be well familiar with this river as a major landmark separating Tokyo from Kanagawa Prefecture, and would do well to get to know it better by pursuing its origins. In fact you can almost do this in its entirely by riding two train lines end to end: the Nambu Line, from near the river's mouth between Kawasaki city and Haneda Airport to Tachikawa, and then from there the Ōme Line to Oku-Tama town centre. A short bus ride takes you the final stretch to the lake.

For this walk, however, get off a few stops before the end, at Kori (古里) station. The whole thing is well-signposted, so between signs, landmarks and basic geography you shouldn't get lost. And as usual, keep an eye out for bears.

From the station's south exit, emerge onto the Ōme Highway at the 7-Eleven ahead and turn right. Follow the road past a primary school and post office, soon turning left onto a side lane as signposted for the Ōtama Trail. Follow this down, across a small bridge then up, and bear left to come to the larger Sunniwa Bridge (寸庭橋) with good river views in both directions.

Look up as well as down, too.

Across the bridge, the main trail starts on the right. Soon after it curves away from the river, look out for a nice secluded waterfall off to the left.

You'll go through a pleasant and straightforward woodland section here, which eventually joins a paved path at a lookout platform with another good view (an ideal place for a lunch stop).

If you go left up the path, you will arrive after some effort at Mitake-san. But for today's purpose go right instead, following it all the way down and ignoring all turnings until you cross the Tama again at Unsen Bridge (雲仙橋).

Across the bridge is Hatonosu (鳩ノ巣), or “pigeon's nest”, along with its stop on the Ōme Line. To continue, turn left once over the bridge and head downhill. You can go straight on at the junction for another little waterfall, but to continue turn left at that junction then immediately right again, and snake down the stairs to Suijin-sama (水神様), the water god's shrine, at the valley bottom.

You can get onto said water god's rock via a path to the left, and it has an overlook with more nice views of the river.

Continuing to the right, you pass the first of two local cafés on this route: Gallery Poppo (ギャラリぽっぽ), the brown building in the photo above. Regrettably, the day of the week I did this walk happened to be its rest day, so it was closed

Across the little bridge behind the café, turn right to proceed through one of the most picturesque segments of the Hatonosu valley. Be aware that you are now approaching the Shiromaru Dam (白丸ダム), which discharges its water according to schedule. If this happens while you are downstream of it then it will come right at you, so be ready to heed the advice of any dam staff you run into, or to hasten to high ground if the dam's siren goes off.

Do not forget that this is the same river as the great wide thing your train crosses between Tokyo and Yokohama.

Soon you come to the dam itself. It was built in 1963, and you can walk across it freely. Its most distinctive characteristic however is its gyodō (魚道), or “fish road”.

Shiromaru Dam.

The view downriver from on top of the dam.

The gyodō is a passage that allows fish to swim past the dam in either direction. It was completed in 2002 and appears an ingenious piece of engineering, with ladder and partition structures that slow the water flow for fish swimming upstream and allow them to rest. All this is open to visitors to see, free of charge: enter the hut in the car park and go down the massive spiral staircase and you can observe the fish on their way. Unfortunately this is closed from December to March, so I missed it this time.

The dam did provide the setting for my most surreal episode of this walk though. Emerging on the far side, an elderly Japanese gentleman with a bicycle and protective mask called out to me, observing that I was a foreigner, and engaged me in what eventually became a 45-minute conversation across a wide itinerary of themes, with particularly long explorations of Iraq and the wrongdoings of British imperialism, all while standing there on that windswept roadside above the dam. Such spontaneous exchanges are another of the frequent highlights of hiking in Japan.

The next section of the trail proper continues back on the side of the dam you arrived on, but has been closed due to a danger of falling rocks since being destabilised by the March 2011 earthquake. Instead, rejoin the Ōme Highway across the dam and continue along it with the river on your left, taking care here because most of this part has no pavement. You will soon pass through another village, where Shiromaru (白丸) station, the next and penultimate stop on the Ōme Line, is nearby on the right.

Before long the highway disappears into a tunnel, just before which you should turn left off it to cross the Kazuma Gorge Bridge (数馬峡橋).

Turning right, another local café is just ahead. The organic Earth Garden Café has an impressive reputation, and offers another chance for a break if the going is getting tiring.

Pressing on along the south side of Kazuma Gorge, you eventually emerge onto a paved lane. Turn right downhill at a large fork, easily identified by this 'amazing piece of unintended profundity', as a certain individual described it.

You are now on the final stretch into Oku-Tama town. Bear left uphill past the Futami Fishing Café, then immediately turn right across the road bridge. Ahead will be a large fork, where the road right leads down across the Tama again; instead take it left, passing a kōban (police box). Bearing right before a tunnel, follow this road all the way to Oku-Tama station.

As you enter the built-up area, keep a look out on the left for the Yamashiroya (山城屋) wasabi shop. Wasabi is one of Oku-Tama's most celebrated products: the fresh river water in this area, flowing through mountain gullies which keep its temperature relatively constant, provides perfect wasabi growing conditions and supports the area's flourishing wasabi farming community. This shop offers fresh wasabi stems at reasonable prices, which can be quite difficult to find in the city, as well as an impressive range of foods incorporating wasabi.

Finally, if you like what you have seen on this walk and would like to explore Oku-Tama further, it is well worth stopping by the Oku-Tama Visitor Centre, on the right just before the station. Plenty of solid information about the area is available there, and two maps especially stand out. One charts where people have got into trouble in the mountains, with said troubles colour-coded into different categories. The other has stickers marking where and when people have seen bears, which noticeably included the town centre itself as well as most of the mountains I have hiked on. (It appears to be standard etiquette to notify the authorities of all bear sightings, so be sure to stop by here if you see any on this walk.)

This is a good walk for warming up in preparation for more serious spring hiking, but is also an excellent option for more casual walkers who want some nice immersion in nature without the ordeals of climbing mountains. And to finish, you can stop somewhere like the Tachikawa “Ramen Square” on your way back to Tokyo for some well-deserved fare.