A decade ago I lived in Tokyo, where I wrote about Japan’s banking woes. For several nail-biting years, I watched as the Bank of Japan unveiled a stream of ever-more creative measures that were designed to combat the risk of a financial meltdown.

By the start of this decade, this crisis was - finally - ebbing away. So when I left Tokyo in 2001, I naively assumed that the BoJ’s “emergency” policies were destined to vanish too.