In the Song Dynasty there was once a magistrate of Bian Prefecture named Tian Deng, who made the uttering of his name by others taboo. This meant that the common people could not speak of deng (lamps), but instead had to call them huo (fire).

As the Lantern Festival approached, on the 15^th day of the first lunar month, the authorities in the prefecture put up a notice allowing the people to light lanterns for the festival. But, because deng (lamp) was taboo, they had to use huo (fire) instead. So the notice read, "According to traditional practice, fires may be set for three days in this prefecture."

Later, the allusion came to be used to mean that the ruling class can indulge in any kinds of excesses, but the common people are not even allowed to pursue their ordinary activities.