CAN bubbles ever pop twice? In late 2009 the world began to worry about a Chinese property bubble, symbolised by Ordos, a newly built city, bereft of citizens, in Inner Mongolia. In the spring of 2010 China’s government broadened its curbs on multiple home purchases and mortgage borrowing. The following spring, prices in nine big cities fell at last, according to one widely watched index. “The Great Property Bubble Of China May Be Popping” declared the Wall Street Journal in June of that year.

This week the same newspaper cited “compelling signs the Chinese property boom is over,” noting that “Cassandras” have been predicting a crash for years. (The Cassandra of Greek myth could tell the future but was never believed. For China’s property Cassandras, things are the other way round: their direst predictions are often believed, but have yet to come true.)