Win a three games of dice in a row. Each 'game' is two rolls of a pair of dice. 7's and 11's win automatically. Otherwise, winning means the totals for the first and second rolls have to be equal to each other.
To start visit the vendor north of social entrance and buy copper bars, then go to the lucky dice rooms on the east side and sayto attend copper.
For beating the house at its own game, the Powers have granted thee a Mark. You have been granted The Mark of Luck! You gain 41 practices!