the empty city stratagem (in which Zhuge Liang presents himself as unperturbed while making it evident that his city is undefended, hoping his adversary will suspect an ambush); double bluff
lit. to sing “The Empty City Stratagem” (idiom); fig. to put up a bluff to conceal one's weakness; (jocularly) (of a place etc) to be empty; (of one's stomach) to be rumbling