Kublai Khan's Chao

Origin
Kublai Khan (1215 – 1294) was the fifth ruler of the Mongol Empire, reigning from 1260 – 1294. Eventually he founded the Yuan dynasty in China as a conquest dynasty which he ruled as the first Yuan emperor until his death. Khan decided that China would be a better fortitude for his reign so he moved from Mongolia there. The Mongol administration had issued paper currencies from 1227 onward. Khan, while ruling the Yuan dynasty, created the first unified paper currency called Chao, bills circulated throughout the Yuan domain with no expiration date. To guard against devaluation, the currency was convertible with silver and gold, also the government accepted tax papers in paper currency. Khan issued a new series of state sponsored bills to finance his conquest of the Song, although the lack of fiscal discipline and inflation made that move an economical disaster. To rectify this Khan took all gold and silver from private citizens and foreign merchants forcing traders to only use the paper money. Due to this Khan is considered to be the first fiat money maker.

Effects
Keeping in possession grants deeper thought, taking it will transfer knowledge but will kill the second person within seven days. Then the turnaround is reset, safe to own again.