General | WEEK 3


Tokyo's real floating world

One interesting phenomenon this year has been the growing popularity of tours to such unlikely places as factories and old bridges, where grimy stone walls, rusting mazes of pipes and crumbling concrete constructions have become a lure for worshippers at the altar of brutalism. In many ways, these tours resemble school excursions designed to broaden students’ social horizons through visits to companies or factories — except that the participants are adults.

When I first heard about a “technical tour of lock gates on Tokyo’s rivers,” I was intrigued in two ways. One was to find out what kind of people join such jaunts, and the other was to discover the aim of the organizer — in this case the Tokyo Metropolitan Park Association, an affiliate of the Tokyo Metropolitan Government.

“This is the first time we have had a lock-gates tour,” said Atsuko Uemura, an official of the association, “though actually this is our sixth technical tour this year.” Previous tours included an aquatic adventure that saw paying parties of the urbanly curious taking a boat trip to check out 19 bridges over the Sumida River in Tokyo. These expeditions, Uemura noted, had attracted a steadily increasing number of the conurbatory curious.

In the Lock Gates Exploration Cruise (¥1,500) that your correspondent embarked on, tourees (yes, you guessed) pass through various lock gates en bateau and generally gawp in mild wonderment at the new perspective on the city that all this provides. Before these thrills, however, the tour starts with a lecture. Had I time-slipped back to a school trip, or what?

So it was that I found myself in a community room in Akashi-cho in Chuo Ward one recent Tuesday morn. Regarding my fellow lockonauts — mostly men in their 50s or beyond — this was, as I had been told, one of those expeditions holding particular appeal for baby boomers with time on their hands and a penchant for mind expansion over more frivolous leisure pursuits.

But then the next moment I was surprised to recognize a familiar face in the group — one of my high-school teachers. She spotted me and smiled, then asked, “What are you doing?” Rapid-fire, I asked geography and science teacher Atsuko Yano the same question back.

“Rivers are my study theme,” she said in a tone reminiscent of a school trip. “I’m interested in how people live in a big city like Tokyo and live and interact with big rivers running through it. That is why I am here using my research time.”

And she was right; there was really a lot of interesting stuff here just waiting to leap out and amaze us all. For example, an association official told us the surprising fact that some areas of northern Koto Ward surrounded by the Sumida River, the Arakawa River and Tokyo Bay are now below sea level due to settlement of the land there that has been reclaimed over the last 300 years. Nonetheless, despite all the embankments protecting them, floods have occasionally inundated such areas — particularly when powerful Typhoon Kitty hit in 1949.

To prevent similar disasters recurring in the area, called the “Koto Triangle,” it has apparently been necessary to control the water level in the rivers as well as building up their banks even higher. Currently, this area boasts high-rise apartment buildings and a population of some 740,000 — but neither would be possible without such protective measures, said the association’s Toshihisa Sakamoto.

Consequently, the locks on the area’s rivers now function both as holding tanks to contain storm surges and as “elevators” enabling boats to pass between two rivers with different water levels. The system is similar (on a slightly smaller scale) to that of the Panama Canal, where three massive locks allow vessels to pass “downhill” or “uphill” between the Pacific Ocean and the Atlantic.

“I didn’t know that Tokyo had lock gates like the Panama Canal,” said Masaru Kamei, 57, one of my fellow voyagers, after the lecture. “It’s quite amazing. I cannot wait to actually go through them.”

So it was with high expectations that myself and 27 others, along with the association officials, boarded our fishing boat that afternoon. The weather was perfect for a boat trip — clear skies and a crispness in the air — but wary of the elements’ fickleness we all donned lifejackets nonetheless.

Teacher Yano sat beside me and told me how she organizes a school trip every year on Tokyo’s rivers from Ryogoku to Odaiba to study the history and geography of the area. But it was the first time for her, too, to ride on a fishing boat that sometimes rocked and more disturbingly rolled. She was well prepared, however, and told me to tell her if I needed any seasickness pills.

We intrepidly cast off from our home port at Akashi-cho on the Sumida River and entered the Onagi River, a stream in the Koto Triangle. Then we entered the Ogibashi Lock from the west and the gate closed behind as we faced another closed gate ahead. When that gate opened, and apparently 2,500 tons of water drained out, we found ourselves ever-so slowly descending by 2 meters to the level of the eastern stretch of the river. The whole process had taken only 6 minutes.

As we passed that second gate, umbrellas were handed out to protect our valiant party from drips. And yes, the closure of the 40-ton gate behind us was indeed a small spectacle of sorts, but the others seemed far more excited than me.

“This is fascinating!” said a 45-year-old engineer at an electronics company who’d taken a day off to join the tour (but declined to be named).

“I knew about the lock gate as I live in the neighborhood,” he explained, “but usually you can’t get close to it and see for yourself. It is very interesting to see the inside.”

Before cruising along to another lock gate, we hove-to at a factorylike site on the Onagi River where huge pumps work to control the water level of the rivers in the Koto Triangle. Participants appeared excited to see all those machines.

From there, high on the canalized ocean wave, we voyaged on to the Arakawa Lock Gate — a titan of its ilk. This gate was completed just two years ago to connect the Kyu Nakagawa River and the Arakawa River, whose water levels we were told can differ by as much as 3.1 meters.

The 65-meter-long, 14-meter-wide lock area partitioned by two gates makes it possible for cargo boats and tankers up to 30 meters long to pass between the two waterways and, having done just that, our humble fishing boat emerged into the huge Arakawa River. This was a prime photo-opportunity moment, and almost all on board were suddenly snapping the setting sun and framing distant and delightful views of the Boso Peninsula in Chiba Prefecture.

It was then that Uemura, from the Tokyo Metropolitan Park Association, told me she hopes that these tours will help a lot more people learn about Tokyo’s rivers and become interested in the city’s various flood-prevention systems.

Although the main business of her section is running boat trips on the Sumida River and the Arakawa River, she said it is also trying to plan more theme-based tours like ours.

For me, though, the tour — while undoubtedly very enjoyable — had been far more technical than I’d imagined from its innocuous description as a “lock gates exploration cruise.”

In fact, I was quite surprised to find that so many people along for the ride with me were already minor authorities on all matters riverine.

“We don’t aim to appeal only to experts, but it’s true that many engineers and architects join our tours,” Uemura said.

“But we also hope more ordinary Tokyo residents will join us next year. Many people love factories and bridges — so why should they not love lock gates, too?”

And for me, it might have seemed a bit like a school trip from years ago — but instead of writing an essay afterward, this time I could have much more fun writing my account for JT readers!

If you are interested in taking one of these trips, call (03) 5608-8922 or visit

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