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The Ming Emperors believed that Song policy had produced a weak, divided polity and had undermined the stability of traditional Chinese society.

purely contingent and accidental reasons. Pomeranz puts great stress on one factor, that China’s coal reserves were both geologically inaccessible and geographically remote, making a steam-powered industrial revolution like the one in Europe impossible

Why did this happen? The simple explanation is the Mongol conquest. However, China recovered from that disaster under the Ming by most measures, and the institutions created under the Song were still extant when the Mongols were expelled in 1368.

By 1370 the population had fallen to half of its level under the Song.

Despite its strengths, Song China never developed an effective military system. Instead it relied on mercenaries, diplomacy, and paying off outside threats.