Ayear after Shinzo Abe gave notice of his plan to restore Japan to economic vigour, the prime minister’s first arrow of massive monetary expansion is flying as swiftly as anyone could have dreamt. The yen is sharply down, the stock market up and consumer price inflation is edging towards 1 per cent, though there are doubts about how long the inflationary flame will flicker. In the first six months of this year the economy grew at an impressively fast annualised rate of 4 per cent. No one has seen anything like it in years.

The third arrow is a different matter. (We will pass over the second arrow of “flexible” fiscal policy since it involves an expansion, then a contraction of spending.) Arrow number three – structural reform – has been fired half-heartedly, if at all. And, the third arrow, says consensus, is what really counts. Without reform and deregulation to lift growth potential, Abenomics will peter out and the economy will be back to square one.

Contrary to consensus, however, Mr Abe’s third arrow is not the most important weapon in his quiver. That distinction belongs to arrow number one. To be clear, no one doubts that Japan needs to raise productivity through structural reform. What country does not? Yet what is really radical about Abenomics is the bold – some say reckless – gamble to rid the country of 15 years of deflation. For the first time, Japan has a central bank governor who says his institution can – and will – hit a specified inflation target. For years, the central bank has strongly suggested that it is powerless to do so. Japan’s salvation, it has said, lies in structural reform. The novelty of Abenomics, in other words, is to reclaim monetary policy.