1 Cash - Wang Mang Fifth reform, 'Biscuit coin'

Wang Mang's currency reforms were among the most aggressive and ultimately catastrophic monetary interventions in Chinese history. Between 7 and 23 AD he imposed no fewer than five separate coinage systems, each devaluing the previous, as his Xin dynasty hemorrhaged legitimacy. The so-called "biscuit coin" of the fifth reform — named for its thick, squat flan — was issued in the final years of his reign as the Eastern Han restoration forces were already closing in.

Wang Mang was killed in 23 AD, ending the dynasty after just fifteen years. His coinage reforms are credited by Han sources with causing widespread economic disruption severe enough to accelerate popular revolt.