To ensure no stragglers miss their cue, the melody plays on a loop — for the final hour and a half.

According to a manager, Panjiayuan has used the tune since 2000. She did not know why.

Image “Going Home,” by the saxophonist Kenny G, has become a staple of Chinese society. Credit... Victor Fraile/Reuters

“Isn’t it just played everywhere?” she asked.

At 9:30 p.m. on Monday, the Powerhouse Gym in central Beijing was a half-hour from closing. As usual, “Going Home” began looping over the loudspeakers, sending the weight lifters and treadmill runners fleeing for the locker rooms. The manager, Zhu Mingde, followed, eager to turn off the lights and lock the doors. Mr. Zhu could not pinpoint when “Going Home” had become China’s adieu anthem, nor could he identify the famous musician behind it. But despite its lack of lyrics, he understood the melody’s cultural significance. “All I know is when they play this song, it’s quitting time,” he said.

For a generation of Chinese youth, “Going Home” has featured prominently on the soundtrack of their lives.

Mao Xiaojie, a junior at the Communication University of China in Beijing, said, “They’d play it over and over again at wedding banquets.”