Japan had a vibrant economy. Then it fell into a slump for 30 years.

Last month, Japan's central bank raised interest rates for the first time in 17 years. That is a really big deal, because it means that one of the spookiest stories in modern economics might finally have an ending. Back in the 1980s, Japan performed something of an economic miracle. It transformed itself into the number two economy in the world. From Walkmans to Toyotas, the U.S. was awash in Japanese imports. And Japanese companies went on a spending spree. Sony bought up Columbia Pictures....