I believe Japan went zero/negative interest after their real estate bubble spectacularly imploded, not before (we are seeing history repeat in China, but much worse). But Japanese lending has always been supported by personal postal savings at low interest rates.
That a huge amount of the country's savings was locked up in state managed postal savings accounts is not normal to most countries, which is why the history section of the wikipedia article is interesting reading. From the article:
> The importance of the Japanese postal banking system lies not just in providing a savings vehicle and financial services to the people of Japan, but also in the use of the saved funds to promote economic development throughout modern Japan's history.
...
> To promote savings which could be invested into rebuilding the economy, Japanese officials issued relentless statements advocating for austerity and instituted measures to restore confidence in the financial system.[10][4] From the 1950s, postal savings experienced steady growth and increased its market share relative to private banks, thanks to the huge availability of postal offices, attractive financial products offering good returns and preferential tax treatment on deposits from the government.[11][4]
