You'll rarely hear the word “bubble” from a Chinese policymaker. Then again, you don't need to. Last week an auction of land in Beijing, zoned for residential development, was cancelled after bidding crashed through an undisclosed ceiling.

In spite of evidence of over-exuberance right on its doorstep, the People's Bank of China is still limiting tightening efforts to the reserve requirement ratio or the proportion of lenders' deposits to be kept at the central bank. Sunday's tweak to the RRR, the third 50 basis-point hike since the beginning of the year, confirms this policy tool as the PBoC's enduring favourite. It has made 29 adjustments over the past decade, compared with 15 to the lending rate and 13 to the deposit rate.

The RRR's attractions are obvious: it costs the Bank very little, compared with open-market operations, while sending out a signal of vigilance. But its effectiveness is debatable. True, three quick-fire hikes during the last three months of 2007 seemed to keep consumer price inflation in check over that period, at just above 6 per cent. But in the first nine months the Bank had given its two other main tools a thorough workout, lifting lending and deposit rates five times each.