Don, the Imperial Currency

Invented by a bureaucrat in collaboration with the Emperor to assist with tracking logistics within the Empire, a form of currency called Don is traded throughout the continent, named after the exasperated record-keeper. Backed and very carefully controlled by the Emperor's own crystalized Sei, Don is used throughout the Feng Empire largely for luxuries beyond one's base needs. As the Empire provides food, water, and so on to its citizens, Don is exchanged for things such as luxury foods, magical items, and anything else beyond the basics. Due to the tight controls on the currency, those in the upper-classes largely measure their "wealth" through status and unique items such as artifacts, artwork, architecture, and so on that they own. As such, commerce between nobility functions more through lavish gift-giving and favors, rather than massive exchanges of money as a magical sword is far less liable to be taxed for having too much of it. Currently, Don comes in four forms, each styled after one of the four provinces, with their value assigned based on when the province officially joined the Feng Empire and measured based on the amount of food one could expect to buy with it:
Gold Phoenix (GP), the most prized, can feed a person for an entire year.
Silver Tortise (ST), the second, can feed a person for a season, or 100 days according to the Imperial Calendar.
Bronze Tiger (BT), the third, can feed a person for a day.
Copper Dragon (CD), the fourth, can supply one meal. The average laborer can expect to earn 12 Copper Dragons a day.