Next, I meet Mona Neuhauss, a half-Japanese, half-German communications consultant who grew up in the United Kingdom and moved to Japan 3½ years ago. Neuhauss runs a business called No Plastic Japan that sells reusable stainless steel straws to individuals and establishments such as cafes and restaurants in a bid to wean them off single-use plastic straws.

Neuhauss’ business sells only a handful of products, but she says it doesn’t take much to make a difference.

“I think we underestimate it,” Neuhauss says. “If one person doesn’t use a plastic bag for a whole year, that’s a huge amount — especially for people who buy something from the convenience store every day, and you get a bag every time.

“It’s not only the impact that you make yourself. People seeing whatever you do can have the effect of spreading. I remember my colleague came over and said she had bought a cup that she was going to use for her coffee. You don’t even realize that you have that effect on them.”

I tell Neuhauss about my plan to stop using single-use plastic for a week, and she warns me it will be tough. “It’s going to be the regular things like shopping for food,” she says. “It’s going to be things like when you need a snack. Anything that comes unplanned is going to be difficult.”

I start preparing by researching how to make my own toothpaste. Most toothpaste tubes are nonrecyclable, and as many as 20 billion are produced worldwide every year. I discover that toothpaste can be easily made at home from coconut oil, baking soda and peppermint oil, so I find some in a specialist baking shop, and buy a bamboo-based toothbrush with pig-hair bristles online. I also buy a shampoo bar that comes wrapped in paper, and get ready to start my challenge.

The toothpaste is very salty and initially unpleasant, but it leaves me with fresh breath and my teeth feel clean. The shampoo bar smells great and works perfectly — but so it should, given that it cost me more than ¥1,000.

Shopping for lunch looks like it could pose more of a problem. I am spending the first day of the week at home, so I take a fabric bag out to try to find some ingredients.

First, I visit a convenience store, and leave almost immediately when I discover that practically the only things I can buy are the fried chicken and steamed buns, which are served in paper or cardboard, on sale at the counter.

Next, I visit a greengrocer. I regularly visit this shop, but I had never really noticed before how many of the fruit and vegetables come pre-wrapped in plastic. Some things are obviously wrapped to group them for price or to protect them from damage, but I do wonder why individual onions or other solid vegetables with skin need to be kept under plastic.

I go to a supermarket and buy two apples and a packet of butter. The cashier doesn’t even raise an eyebrow when I say I have brought my own bag. I go to another greengrocer and buy lettuce. The person serving me thanks me for not taking a bag. So far, so good.

I then beat a hasty retreat from a bakery whose products are all pre-wrapped, then buy a tomato, five potatoes, a carrot, an onion, a jar of jam and a can of tomatoes at a supermarket. The cashier is unconcerned when I say I don’t want a bag, but she looks at me like I’m some kind of eccentric when I say I don’t want my potatoes placed in a smaller plastic bag either.

I am beginning to feel slightly embarrassed, and that only increases when I buy three slices of ham at a different supermarket’s delicatessen counter. The clerk agrees to wrap them in paper, but he tells me they might fall out if he doesn’t then put the package in a plastic bag. When I ask him not to, he looks at me like I’m a full-blown lunatic.

There is another awkward moment when I buy a baguette and a smaller piece of bread at a bakery. The clerk puts the baguette in a paper bag but puts the other piece of bread in a plastic bag. My request to put both in paper is met with confusion, and as I’ve had enough of making a fuss in shops that I often visit, I smile, accept defeat and take my plastic-wrapped bread back home.

My shopping trip has taken an hour, and has involved eight different shops over a fairly wide area. I eat a ham and salad sandwich for lunch, followed by an apple.

I have managed to find some of the ingredients to make a shepherd’s pie for dinner but I still need to buy some ground beef, so after lunch I take my Tupperware box to the butcher. He happily agrees to put the beef in it, but when he gives it back to me, I realize he has slipped a thin plastic sheet underneath the meat as well.

“The shop is not responsible for what happens to my bag later,” Neuhauss had told me when I met her. “Customers need to be aware that that’s OK. If something leaks in my bag, that’s my fault for not doing it properly, and shops should be OK with that. In the U.K., I couldn’t imagine someone complaining to a shop that a yogurt leaked in their bag. We need to shift what we see as good service.”