"This vibrant craft brew scene is a recent development—in part because it was actually impossible not long ago. Before 1994, microbreweries were illegal in Japan. Licenses were granted only to brewers producing well over half a million gallons a year. That protected the well-entrenched large brewers from any upstart competition."
The current Japanese regulations, which grant licenses to breweries which produce over 60,000 liters a year, grew a market for microbreweries in the same way that deregulation in the U.S. did after 1979. The number of Japanese microbreweries exploded after 1994, peaking at over 300 in 1999. There are still well over 200 craft beer producers in Japan making beer so "alarmingly good," only deregulation could be responsible.