Japan's economy stagnated in the 1990s after its stock market and property bubbles burst. Companies focused on cutting debt and shifting manufacturing overseas. Wages stagnated and consumers reined in spending.
Once deflation set in consumers started to expect prices to fall and they delayed spending for as long as possible in order to save money. That perpetuated the problem and continued the cycle.
Japan’s ageing population is now making the problem even worse. By 2020 the country will be losing around 600,000 people a year. Getting growth from an ageing, shrinking society is difficult.