BEIJING • The most shared post on Weibo, China's Twitter-like social media platform, is not a video of frolicking pandas or President Xi Jinping meeting world leaders, but a teenage boy's birthday message: "I'm 15 today. Thanks for being with me all these years."
Since that was posted in September 2014, it has been shared more than 335 million times, the most shared Weibo post ever, according to Guinness World Records.
The post was by Wang Junkai, leader of TFBoys, a wildly successful boyband in China. Since their debut in 2013, when the boys were just 12 and 13, they have won major Chinese music industry awards and amassed more than 20 million Weibo followers. Sales of band merchandise average more than US$17 million (S$24 million) a month, according to Chinese news reports.
So what explains their appeal?
"I like them because they express such positive values," said Ms Jia Su, a 24-year-old advertising worker in Beijing. She has followed the group since she was a university student and now manages the Weibo account of a fan club for TFBoys. "They are nice, kind, hardworking. That's what the Japanese and Korean boybands don't have."
Unlike many teenage pop stars elsewhere, the members of TFBoys display no signs of youthful rebellion. They sing of studying hard and serving the nation. Their music is cheerful with upbeat lyrics and their appearance tends towards neat outfits and sweet smiles.
The group are no accident, having been formed by a company, Time Fengjun Entertainment, using three boys - Wang Junkai, Wang Yuan (no relation) and Yiyang Qianxi - plucked from its trainee programme.
The video for one of their most popular songs, Manual Of Youth, shows them dancing with comic-book superheroes in a classroom aglow with pastel colours.
That wholesome schoolboy image has won TFBoys love not only from Chinese fans, but also from the government. They have twice been featured on the Chinese New Year television gala staged by CCTV, the state broadcaster. The Communist Youth League's official Weibo account often promotes the group's activities.
On International Children's Day in 2015, the Communist Youth League released a video featuring TFBoys singing We Are The Heirs Of Communism, the song of the Young Pioneers, the communist children's organisation.
"One way the Chinese government controls the entertainment industry," said Mr Zhu Dake, a cultural critic at Tongji University in Shanghai, "is by honouring and financially rewarding those who, from the government's perspective, are conveying positive values."
The Chinese authorities are quick to discipline celebrities who break the rules, whether by indulging in illicit drugs, soliciting prostitutes or demonstrating sympathy for Hong Kong or Taiwanese "separatists".
Recent victims have included South Korean entertainers. Since South Korea agreed last year to allow the United States to install a missile defence system,South Korean singers and actors have been barred from Chinese television.
Mr Zou Dangrong, chief executive of the Hunan Dangrong Film and Television Media Centre, which trains people to become online celebrities, said the TFBoys' success was also a sign of the progress of China's entertainment industry.
"Before the early 2000s, the mainland Chinese entertainment industry was dominated by Hong Kong, Taiwan, Japan and South Korea. Celebrities from those places were regarded as true stars," he said. "But it's different now. We have the money and the market."
The TFBoys' fame is reaching beyond the music industry. Wang Junkai had a role in Zhang Yimou's 2016 movie The Great Wall. Wang Yuan appeared in the film adaptation of popular writer Guo Jingming's fantasy novel L.O.R.D.: Legend Of Ravaging Dynasties.