Earthquakes are a fact of life in Japan, perhaps the most fundamental one.
When I moved to Tokyo some years ago I wrote home to tell my family of my first earthquake experiences.
“Surely you mean tremors,” they replied. “We haven't heard anything about an earthquake.”
But the distinction between a quake and a tremor, so apparently obvious in Britain, is not one that impresses the Japanese.
It might start as a tremor, a rocking sensation accompanied by a faint squeaking in the rafters, but where is it going to end?
Most just fade out after a few seconds. Others, like yesterday's, start mild and harmless.
But then suddenly things are falling off shelves, the walls are heaving back and forth and there is a deep rumbling coming up from the foundations. Then you know it's time to dive for cover.
Earthquakes are like mid-air scares in airplanes: far from getting used to them, they get scarier the more of them you go through. There were few reports of outright panic from Japan yesterday despite the unprecedented, disaster-movie scale of what was unfolding, but that is social discipline, not absence of fear.
In fact the legendary discipline of the Japanese may have developed as a way of coming to terms with their seismic environment without losing control.
And Japan may be the only country in the world which has really come to terms with the damage earthquakes can do, and not only enacted appropriate laws but also enforced them. That alone singles it out from the vast majority of countries where the quakes are a frequent menace.