As the US Federal Reserve and other major central banks embark on vigorous interest rate rises to combat inflation, Japan is now the only country in the world that still has negative rates. It paid the price for that position on Thursday, after the Swiss National Bank lifted its rates into positive territory. A pledge by the Bank of Japan to stick with its ultra-loose monetary policy drove the yen to a 24-year low. Within hours, Tokyo intervened to buy its own currency for the first time since the late 1990s.

This action is unlikely to have any useful economic effect, but nor is it likely to do too much harm; and given the political struggles of Fumio Kishida’s government it is understandable. Japan’s G7 partners should not protest too loudly.

The yen has lost about one-fifth of its value against the dollar this year, the slide accelerating as the Fed’s rapid monetary tightening has opened a significant interest rate differential.