A few weeks before my son started first grade, I asked my friend Nagako to help me read the list of school supplies I needed to buy.

We were going down the list — hasami (scissors), iroenpitsu (colored pencils) — when we got to the item that always strikes me as odd: zokin (cleaning rag). I stopped and commented on it to my friend.

Nagako looked at me blankly. “Why is that funny? What do American kids use to clean at school? A mop?”

“American children don’t clean at school. There are adult employees called janitors or custodians who do all the cleaning,” I replied.

She was shocked. One of the traditions of Japanese education is that students do o-soji (cleaning). It had never occurred to my friend that things might be different elsewhere.

“Actually, Japan is famous for o-soji,” I told her. “That’s one of the few things foreigners tend to know about Japanese schools.”

Unfortunately, those foreigners tend to get the details wrong. I’ve twice seen in print the assertion that Japanese schools have no janitors because students do all the cleaning. I saw this once in the New York Times and once in a book from a reputable university press.

It’s simply not true. Japanese schools have non-teaching staff called yomushuji, or shuji for short. They have many responsibilities, including serving as crossing guards when school lets out, but their main job is cleaning and maintenance.

It’s a good thing, too. I’ve watched students clean on several occasions. Schools definitely need adults to mop things up after the kids finish cleaning.

At our school, o-soji starts after lunch and lasts 20 minutes, after which the kids are set free for recess. This happens four times a week (they don’t clean on Wednesday or Saturday). On the last day of each semester, there is a longer sprucing-up called osoji (big cleaning). Throughout cleaning time, the public announcement system blasts cheerful marching music (“the o-soji song,” my kids call it).

Every class is responsible for cleaning its own classroom and two other places in the school. My son’s fourth-grade class is currently in charge of the nurse’s office and the library. The class is divided into han (small groups), each of which is responsible for one of the areas to be cleaned.

Here’s one assignment I find really sweet and typical of the attention to human relations at Japanese schools: A group of sixth-graders is sent to each first-grade classroom to help the little kids clean. Many schools provide this kind of interaction between the upper and lower grades because so many Japanese kids are hitorikko (only children, i.e., they have no siblings). Teachers believe older students need to experience helping younger children. And little kids need older role models.

Three times a year, students in third grade and above do chiiki seiso (neighborhood cleanup). The school has an arsenal of kid-size brooms and dustpans that are brought out for the event. The kids put on cotton-knit gloves called gunte (another item on my list of school supplies) and head out to pick up trash in the neighborhood around the school.

Not all schools bother with neighborhood cleanups anymore. I heard on television recently that littering by Japanese teenagers is on the increase. A commentator on the show suggested that more middle and high schools should organize chiiki seiso. If teenagers had to pick up trash around their school, maybe they’d think twice before littering, he said.

Naturally, some kids are more serious about cleaning than others.

Recently I observed a group of third-graders assigned to clean the center staircase. Two girls were deeply immersed in chatter as they stood on the stairs, wiping one spot on the handrail over and over. A boy had flopped himself down on the landing, his legs splayed out in front of him, his left hand idly sliding a dirty zokin back and forth on the floor.

My son happily confessed to me that when he was in third grade, with responsibility for those stairs, he and his classmates would drop cleaning rags down the hole in the center of the staircase. Then they’d race to see who could be the first to get down three flights and return with his rag.

Schools vary in how much emphasis they put on o-soji. Our school draws the line at the toilets, which are cleaned by the shuji, not the students. But at a friend’s school in Chiba, fifth- and sixth-graders get latrine duty. (They hate it, naturally).

One of my tennis partners sends her kids to a prestigious private elementary school. Her big dissatisfaction with the education they receive is that the school doesn’t require students to clean.

“Where are they going to learn to clean if not at school?” she complained to me recently. “I certainly can’t get them to clean at home. I don’t think either one of them has the slightest idea how to use a broom and dustpan!”

At the other extreme is a private girls’ school near Yotsuya in Tokyo. Despite its reputation as an o-josama gakko (school for spoiled, rich girls), students there are expected to be unusually thorough when cleaning. I hear the toilets at that school sparkle.

It’s a little hard for non-Japanese to grasp why kids should be cleaning at school. With all the concern about falling academic achievement, shouldn’t they be using that time for learning?

But students are learning during o-soji, Japanese parents and educators will tell you. They are learning to respect their surroundings. They are learning that it’s better not to make a mess if you are the one who has to clean it up.

Having watched the students at our school clean, I’m a little skeptical. I don’t think many kids are taking those lessons to heart. And while I wish I could report an improvement in my own children’s habits since they started attending Japanese school, they are as messy as ever.

Still, I’m going to keep an open mind and hope they are building character and learning to respect public space.

If nothing else, maybe they’ll learn how to use a broom and dustpan.