William Henry Wilkinson suggests that the first cards may have been actual paper currency which doubled as both the tools of gaming and the stakes being played for, similar to trading card games. Using paper money was inconvenient and risky so they were substituted by play money known as "money cards". One of the earliest games in which we know the rules is "madiao", a trick-taking game, which dates to the Ming Dynasty (1368–1644). 15th-century scholar Lu Rong described it is as being played with 38 "money cards" divided into four suits: 9 in coins, 9 in strings of coins (which may have been misinterpreted as sticks from crude drawings), 9 in myriads (of coins or of strings), and 11 in tens of myriads (a myriad is 10,000). The two latter suits had "Water Margin" characters instead of pips on them with Chinese to mark their rank and suit. The suit of coins is in reverse order with 9 of coins being the lowest going up to 1 of coins as the high card.