[1] https://en.wikipedia.org/wiki/List_of_tornadoes_and_tornado_...
I grew up on the edges of the New Madrid fault area and, while earthquakes were never discussed, we did tornado drills about every two months while in school. After I entered the workforce, that got closer to once a year, but you were still expected to have a plan and supplies. It was basic emergency preparedness, like any sensible person. Granted, big F5 tornados are rare, but small ones were common enough to not even be noteworthy.
Having left that region as an adult, it was a small culture shock meeting people who never had this kind of training. After all, the places I've visited all experience tornados, though not as often as my old home town. Still, the usual attitude I encounter is "I've never seen a tornado - they don't happen here". It's true that tornados don't happen often, just like my birthplace hasn't seen a serious earthquake in my lifetime, but they do happen.
I guess that's why I'm curious about your experiences. I've never been to Japan and I've read enviable reports of your disaster preparedness, but I honestly have no idea how your schools and culture handle tornados.
That said, it is very common and normal for people to keep emergency backpacks that they can grab and take to shelters if there's an evacuation. I have one in the closet next to my front door. The government also periodically gives out free emergency supplies for people to keep. There's publicized evacuation plans and routes, and places seem like they're prepared for big storms: subway stations for instance have huge doors at the entrances to protect against flooding.
It wouldn't make sense for every place to prepare as much as Japan for things that are less likely there than in Japan. Does Japan have as many tornado shelters as Kansas? Probably not.
Except nuclear reactor backup systems </tongue in cheek>