A house in Japan isn't good for much if it can't stand a bit of shaking from a major earthquake. Considering that Japan is entering a 'seismically active period', having a house that doesn't wobble too much is desirable.
As if on cue, we were treated to a couple of decent jolts numbering 4 on the Japanese scale of intensity. This is not a killer quake by any means, but the house didn't sway about for minutes afterwards as our last one did after a tremblor, so I'm reasonably confident that we won't fare too badly in something bigger.
This earthquake struck a good distance to the east of Matsuyama, and was felt over a wide area of south western Japan.