I just got an epiphany after PG mentioned the merchant class in China. Big advancement such as gun powder, movable types was invented in Song Dynasty. Song Dynasty was in fact one rare period in China that had a pretty vibrant merchant class. But after Ming Dynasty, most Chinese historians judged Song Dynasty as a pretty lame era. ("smaller territory, continuous conflicts with northern enemies and finally lost to Mongol) But from economics history aspect, Song dynasty was a pretty well developed period.

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Wikipedia has a pretty good summary of Song Dynasty. And one reason for the economic development in Song was the government loosed regulations on market economy... Does this sound familiar to anyone?