One could almost hear the sighs of relief from the Bank of Japan yesterday when it announced the end of its unorthodox policy of "quantitative easing". Normality comforts central bankers. Being forced to provide large quantities of liquidity to the commercial banks was abnormal and uncomfortable. But in abnormal situations, unconventional policies are the right ones. In ending the policy, the bank is taking a risk with something that matters far more than any discomfort, namely, the stability of the Japanese economy.

The bank introduced the policy of quantitative easing to augment the effectiveness of the zero interest rate policy, followed - with a short and disastrous break in 2000 - since 1999. The aim was to increase the liquidity of the commercial banks' balance sheets and so increase the money supply and, indirectly, the commercial banks' willingness to lend. Today, the quantity of such reserves stands at Y35,000bn (£170bn). This is vastly above the Y6,000bn believed necessary to keep short-term interest rates at zero.