This one goes north, out of the tourist district and into the part of Asakusa where people live. That changes how you should behave. These are working streets and private homes. Photograph buildings, not people's windows, and keep your voice down — the audio is in your ear, not theirs. About an hour, eight stops, flat the whole way. Start behind the temple, at the smallest amusement park you will ever see.

Two streets behind the temple, wedged in between houses, is the smallest amusement park you will ever see. Stand outside the entrance, on the street, and look up over the fence before you decide whether to go in. What you can see from here is most of it. That is not a joke about the view — the entire park fits on a plot of land smaller than a supermarket. There is a tower, some track, a couple of rides, and then immediately, on every side, apartment buildings with laundry on the balconies. People live hard up against this thing. Somebody's bedroom window looks directly onto a roller coaster. Hanayashiki opened in 1853, which is before Japan had reopened to the world, and it was not an amusement park at all. It was a flower garden — somewhere to come and look at peonies and chrysanthemums, laid out at a time when this was the edge of a temple town. The rides arrived gradually, decade by decade, and the flowers lost. It now holds the title of the oldest amusement park in Japan, which it earned by outlasting everything built after it. The roller coaster dates from 1953 and is the oldest in the country. It reaches about forty-two kilometres an hour, which sounds thoroughly unalarming until you watch where it goes. It runs between apartment buildings. It passes through a gap in a wall. At one point it travels over the roof of a neighbouring structure. Nobody would be permitted to build that today, anywhere, and the reason it exists is simply that it was already there before the rules were. Look at how the park handles having no room, because it is the most interesting thing about it. There is no horizontal space, so everything went upward and inward: rides stacked over other rides, track threaded through gaps, walkways running under structures. Nothing here is laid out. Everything here is fitted in, the way you pack a suitcase that is already full. You do not have to go in, and this walk does not depend on it. But notice what the scale is telling you, because it sets up everything else you will see this afternoon. This is what entertainment looked like in a city where land was already too valuable to waste, and where nobody had yet had the idea of putting the fun somewhere else. A modern theme park sits on reclaimed land an hour from the city and is surrounded by car parks. This one is surrounded by people's kitchens, because it was built for the people whose kitchens those are. That is the pattern for the whole of Oku-Asakusa. Nothing up here was placed for visitors. It was placed for the people who were already living here, and it is still standing because they are still living here. Now walk north. Within about three minutes the crowd will simply stop, and you will notice the moment it happens.

You are on Senzoku-dori now, and the first thing to do is stop and notice what changed. The volume dropped. There is no queue anywhere. Nobody is standing in the middle of the street taking a photograph, and — this is the one that takes a moment to register — nobody is trying to sell you anything. Not one person in this street is looking at you hopefully. You are about six hundred metres from the busiest shopping street in Tokyo. Look at what is actually on sale. Fish. Vegetables. Futons. School uniforms. Reading glasses. Slippers. A shop that repairs watches. There is no version of any of this that works as a souvenir, and that is because none of it is meant to be one. What you are standing in is a shotengai — the neighbourhood shopping street that was the basic unit of Japanese urban life before supermarkets and convenience stores took the trade away. Thousands of them have closed across the country, and the ones you find with shutters down all the way along are the more common outcome. The survivors tend to be in districts with an older population who still shop daily rather than weekly, buying today's dinner today. That is exactly what this is, and it is why it is still open. Two things to do while you walk it. First, look at the prices in the greengrocer. Then compare them to what you paid for lunch near the temple. Six hundred metres, and it is a completely different economy — one of them is priced for people who came once, the other for people who will be back tomorrow. Second, look up. Count how many of these shops have a residence on the floor above. Most of them do. The shopkeeper lives over the shop, which means the rent is not a cost that has to be earned before anything else, and it means somebody is here at night. That single arrangement — living over the work — is most of the reason this street still functions when so many others did not. While you are looking up, notice the roof over the street. That arcade is not a decoration either. It means this street works in rain, in August heat and in February wind, which matters enormously if your customers are people who come out every single day and many of them are old. A covered street can hold a daily habit. An open one loses it to the supermarket the first wet week of the year. One thing about how to be here. Nobody is expecting you, and that is genuinely the point, so do not treat the street as a display. Photograph the shopfronts if you like; do not photograph through a doorway at somebody having their tea. If you want to do the single most useful thing a visitor can do in a place like this: buy something small. Not as a gesture. A shotengai stays open on daily turnover, and you are a customer like anybody else for about two hundred yen. Keep going north to the shrine.