Exhibitions by the Gao brothers, whose work the authorities find politically challenging, have been shut down in the past, and their studio has been raided. So they keep the head of Mao hidden in a separate location, reuniting it with its body only on special occasions to show friends and colleagues. Normally, the body of the statue remains headless, unidentifiable and nonthreatening. ”It’s something I hope all Chinese people will one day be able to accept and understand,” Gao Zhen, 53, said of the work. “We wanted to portray him as a human being, a regular person confessing for the wrongs he’s committed.”

Removable heads and underground exhibitions are just two of the guerrilla tactics the Gao brothers have employed, often with the help of Melanie Ouyang, their broker, to enable fans and friends to view their work. The Gaos are part of a generation of avant-garde Chinese artists who are pushing the boundaries of artistic expression. In the increasingly open Chinese art world, nudity is commonplace where it used to be forbidden, and art parodying the Cultural Revolution has become so ubiquitous that it is passé. Still, the Gaos are a reminder that, especially as China celebrates the 60th anniversary of the Communist revolution, limits to expression remain: although artists are increasingly free to deal with social and political topics, works that explicitly criticize Chinese leaders or symbols of China are still out of bounds.

“Ash Red,” a 2006 exhibition the Gao brothers openly advertised and held in their studio, was suppressed by authorities. Posters and catalogs for the show were banned, and interviews the brothers had lined up with local news media were canceled. For several weeks after “Ash Red” was shut down, two guards stood outside the doors of the Gao brothers’ home studio, discouraging people from coming inside.

For the Gao brothers, Mao holds a more personal meaning. During the Cultural Revolution their father was labeled a class enemy and dragged off to a place that was “not a prison, not a police station, but something else,” Gao Zhen said. After twenty-five days had passed, the family members were told he had committed suicide.

They think otherwise: “If someone didn’t like you at that time, they arbitrarily labeled you a class enemy,” Mr. Gao added. “We came to Beijing to petition our father’s death.” Eventually the family was given the equivalent of about $290 in compensation. “That was a very painful period of our life,” Mr. Gao continued. “We were six brothers and a single mother; we didn’t have a penny.”

Still, many Chinese who are critical of the Gaos’ work say it lacks subtlety. “I understand what they’re trying to say, but I think their pieces are sensationalist—they’re too direct and gaudy,” says Feng Ling, 23, an art student who recently came to the Gao brothers’ home studio and saw “The Execution of Christ,” in which a firing squad of Chairman Maos take aim at Jesus.

“The Gao brothers’ work on Mao is provocative for many mainland Chinese,” said Kai Heinze, 33, director of the Faurschou Gallery. “Their work sets off a trigger, challenging people here to understand and tolerate a view of modern Chinese history that admits shortcoming,”