The hottest topic in Silicon Valley is the rise of the so-called unicorns -- privately held tech companies valued at $1 billion or more -- in many of the globe's leading economies.
But not in Japan. While the U.S has 112 of the 222 such businesses in the world today, Japan has just one, according to CB Insights, a research group. That is far fewer than China with 59 or even India with three. Why this yawning gap between Japan and other big economies?