Rainbow Bridge

Listen first. Under your feet there is a low, steady hum. It is the sound of traffic moving across the deck above you, and of the trains running beside you. Salt air comes off the water. Gulls turn over the bay. The white towers rise ahead, and the steel cables sweep down from them in long, clean curves. You are standing on the Rainbow Bridge, a suspension bridge that carries people, cars and trains across the northern edge of Tokyo Bay.

The bridge links two very different shores. Behind you, on one side, is Shibaura, an old harbour district of warehouses, piers and office towers in Minato Ward. Ahead lies Odaiba, a waterfront area built on reclaimed land. The bridge opened in 1993. At that time Odaiba was still largely empty ground, and the bridge was part of a plan to turn this land into a new city district by the sea.

Here is the first surprise. The name you know is not the official one. In Japanese records, the structure carries a much drier title, which translates roughly as the Tokyo Port Connector Bridge. The name Rainbow Bridge came from a public naming contest. People liked the idea of an arc of colour over the bay, and the name stuck so firmly that almost nobody uses the official title today.

Now look at how the bridge is built. It has two decks, one stacked above the other. The upper deck carries the Shuto Expressway, the elevated toll road network of Tokyo. The lower deck holds an ordinary road in the centre, the tracks of the Yurikamome line, and two walkways for people on foot. So as you walk, you share the bridge with three kinds of traffic at once.

The Yurikamome is worth a moment of attention. It is a driverless train that runs on rubber tyres, so it moves quietly compared with a normal railway. On the Shibaura side, the line needs to climb high enough to reach the bridge deck. Instead of a long, straight ramp, the track turns in a wide loop to gain height. If you ride it, you feel the train circle around before it heads out over the water.

The main span between the two towers is long — roughly 570 metres. That gap is not an accident. Large ships enter the inner harbour here, so the deck had to rise high above the water and leave a wide, clear channel below. Look down from the railing, and you may see a container ship or a ferry pass far beneath you. From this height, even big vessels look small.

There are two walkways, one on each side of the bridge, and they give you two different views. The north side faces the city. From there you see the towers of central Tokyo, the harbour edge, and on a clear day the red and white frame of Tokyo Tower. The south side faces the open bay and Odaiba itself. Many people walk out on one side and return on the other.

Now for the second surprise. Look out at the water on the Odaiba side, and you may notice small, square islands with trees growing on them. These are old gun batteries. In 1853, American warships under Commodore Perry arrived in this bay, and the military government of the time grew alarmed. It ordered a line of artificial island forts to defend the capital. The Japanese word for such a battery is daiba — and that is where the name Odaiba comes from.

Only a few of those forts survive. One of them is now a public park on the Odaiba shore, where you can walk along the old stone walls. Another stands alone in the water and is closed to visitors, so nature has taken it over. So while the bridge belongs to the late twentieth century, the name at its far end goes back to a moment of national fear, when Japan was about to open to the outside world.

As evening comes, the bridge changes. Lights come on along the cables and towers, and the whole structure glows against the dark water. Most nights the lights are white, which surprises people who expect a rainbow every night. On certain special occasions, the bridge is lit in several colours. Below it, small wooden pleasure boats with paper lanterns drift across the bay, carrying groups of people who eat dinner on the water.

The walk itself is a simple pleasure. The walkways are fenced in, so you look out through a screen of metal and glass, and the wind can be strong. The noise of the trains and trucks is constant, and the deck vibrates slightly as heavy vehicles pass. That vibration is normal. Long suspension bridges are designed to move a little with wind and load. Take your time, and stop often to look back.

When you reach the Odaiba end, the scene opens up. There is a sandy seaside park along the shore, where people sit and watch the bridge. There is also a small replica of the Statue of Liberty, placed on the waterfront, with the bridge rising behind it. It is an odd pairing — an American symbol in front of a Japanese bridge — and it has become one of the most common photographs taken in this part of the city.

Before you move on, stand still for a moment. Feel the wind coming in from the bay, and the faint movement of the deck below you. Watch a train slide past, quiet on its rubber wheels. Look at the old fort sitting in the water, and then at the glass towers on the shore. As you walk away, turn around once more. The white towers will still be there, holding the bridge high above the harbour, between the old port and the new city.