On April 15, the day after the first earthquake struck Kyushu, all of the nation's major newspapers carried the same headline: "Shindo 7 in Kumamoto." No further explanation was needed.

When Japan's earthquake-battered populace feels the ground shake, it looks to its TVs and Twitter feeds to check not only the magnitude, but the shindo, or shaking intensity.

On every TV channel, digital overlays report the region hit and show waves of numbers rippling away from the epicenter: one area might register as shindo level 3, defined as "felt by most people in that zone," another as level 4 ("most people are startled"). The first magnitude estimates typically come later.