I am skeptical whether you have drawn the correct conclusion from your experience in Japan. There seems to be something else going on beyond just taking hygiene seriously.

https://noahcarl.substack.com/p/why-have-there-been-so-few-c...

Early in the pandemic they also understood the issue of poor airflow and took that seriously. For example, on the trains (even in winter) they keep a number of the windows open to ensure airflow. Schools were required to keep the classroom windows open and breaks were required at set intervals to ensure people were moving in and out of the classrooms. Restaurants were requested to keep their windows and doors open.

To be honest, I don't think hygiene is taken seriously here. Most people don't wash their hands after using the bathroom, especially at home. That said, they also don't shake hands, and they do use hand sanitizer and wipe their hands with towelettes before meals.

I think what OP really means here is the universal mask usage, which is common during flu (and allergy) season, which definitely had an impact.

Of course, Japanese people rarely take off work when they're sick. They're actively discouraged from doing so, as almost no companies offer sick leave. You're required to take your sick leave from your vacation time, and most companies offer less than 10 days of vacation time. I think the most impactful thing during covid is that the government actively pushed companies to allow work from home, which is a major shift in how people work here. I, for instance, have never gone into the office (I started during covid) and my company is allowing work from home as the default, forever.

The government response as a whole is pretty comical, and they can't really be given much credit. They started a "travel around the country" program called GoTo Travel, which definitely resulted in covid being spread from Tokyo around the country, during one of their larger waves. Their vaccine roll out has been one blunder after another.

Overall, I think the way the culture works here, and their past experiences with SARS, and their normal handling of the flu, is why the country hasn't been overrun, even though it's mostly stayed open the entire time.

I think the article leaves a lot of space for the possibility that the Japanese have kept infections low because it is a low physical contact culture, and that there have been fewer deaths due to the lack of obesity.

Those are possible hypotheses but remain unproven.