TOKYO -- An all-girl pop group portrayed by some as the Chinese version of Japan's AKB48 is now in the political spotlight -- for singing the praises of the disastrous 1966-1976 Cultural Revolution during a recent concert.

The 56 Flowers concert was held at the Great Hall of the People in Beijing on May 2. As things stand now, the incident remains shrouded in mystery. Will anyone face the music over the affair?

The controversy comes at a politically sensitive time: Monday is the 50th anniversary of the start of the Cultural Revolution.

Exactly half a century ago, Mao Zedong, who brought communism to China, launched the socio-political movement as part of his struggle for power.

On May 16, 1966, the Chinese Communist Party released an official document that became known as the "May 16 Notification." In accordance with the document, the Central Cultural Revolution Group was set up.

The group included Jiang Qing and other radical supporters of Mao. Jiang, Mao's last wife, became one of the "Gang of Four" leaders of the Cultural Revolution. Eventually, she was arrested and punished.

The Cultural Revolution claimed numerous victims. The Chinese Communist Party has since rejected the 10-year catastrophe and pursued a policy of "reform and opening-up."

U.S. running dogs

During the May 2 concert, the 56 Flowers sang songs praising the Cultural Revolution. A huge picture of Mao in military uniform hung behind them.

It was a scene reminiscent of a high-profile campaign launched by Bo Xilai, the disgraced former Communist Party chief of Chongqing, who promoted "red songs" eulogizing Mao. Bo is now serving a life sentence on a corruption conviction.

The concert also included at least two relatively new songs eulogizing Chinese President Xi Jinping. One of the songs is about his surprise visit to a cheap steamed dumpling restaurant in Beijing in 2013, when Xi ate alongside ordinary citizens.

The songs -- which praise Xi for having a common touch and smack of personality cultishness -- have effectively been approved by the Communist Party.

The steamed dumpling shop where President Xi Jinping made like an ordinary citizen in 2013

When the pop anthems were created, many intellectuals and others in China frowned as the songs evoked bitter memories of the Cultural Revolution.

During the May 2 concert, an anachronistic Cultural Revolution-era slogan was shown: "The people of the world should unite to defeat the U.S. aggressors and their running dogs."

This is the kind of anti-U.S. rhetoric that only North Korea still uses.

The "May 16" girls

According to a Chinese newspaper report, the 56 Flowers idol group was formed to sing red songs and other numbers for the Communist Party. Despite its miniskirts, the troupe has a nationalistic tinge.

The group is said to have a strong sense of rivalry toward SNH48, a sister group of Japan's AKB48 operating primarily in Shanghai. A former member of the 56 Flowers reportedly got the boot after secretly auditioning for SNH48.

The 56 Flowers group is said to have close relations with China's Ministry of Culture; a ministry sign hangs in its training hall. It is also said to enjoy the support of the Publicity Department of the Communist Party's Central Committee, which is charged with controlling the media, and the Communist Youth League, a ruling party youth organization.

The idol group is made up of 56 young women representing China's officially recognized 56 ethnic groups.

Wu, shi and liu mean five, 10 and six. Wu-shi-liu literally means 56 but can be interpreted (by political pundits) as meaning May 16.

According to a news site operated by state-run Xinhua News Agency, the May 2 concert was co-sponsored by an office of the Communist Party's Publicity Department, a committee of the party's Communist Youth League and the China National Opera & Dance Drama Theater.

Backhanded compliments

The concert reportedly attracted a full house, with many Communist Party and military officials as well as ordinary citizens seated in the Great Hall of the People.

It also drew a quick protest from Ma Xiaoli, the daughter of Ma Wenrui, a former labor minister and vice chairman of the National Committee of the Chinese People's Political Consultative Conference, the country's top political advisory body.

Ma Xiaoli sent an open letter to Li Zhanshu, the director of the Communist Party's General Office and one of President Xi's close aides, claiming that the event praising the Cultural Revolution is a clear violation of the party's rejection of the socio-political movement.

Like Xi, the sharp-tongued Ma Xiaoli belongs to both the Princeling faction and the second red generation. Princelings are the children of prominent and influential senior party officials, while the second red generation is a smaller group of children of revolutionary-era party leaders.

Xi's father, Xi Zhongxun, once served as China's vice premier. Presidnet Xi and Ma Xiaoli are childhood friends. They attended the same primary school. They shared similar circumstances when they were young. Their fathers were both persecuted during the Cultural Revolution.

Through the open letter, Ma warned against China's shift to the left. Her gambit paid off.

On May 6, two organizations involved in the concert issued statements claiming to have been deceived. The two bodies are the China National Opera & Dance Drama Theater, one of the sponsors, and the cultural committee of Beijing's Xicheng District, which approved the event.

They said an office in charge of the promotion and education of "socialist core values" at the Communist Party's Publicity Department had not actually co-sponsored the show.

Shortly afterward, some online sites deleted reports about the concert. Wiped away were photographs and statements issued by the China National Opera & Dance Drama Theater and the cultural committee of Beijing's Xicheng District. Access to other concert-related material has been restricted.

It is clear that a heated debate has broken out within the Communist Party.

The statements by the two organizations explain that the Communist Party's Publicity Department had nothing to do with the concert and that they had been deceived. But the obvious question remains unanswered: Who deceived them?

The mysterious May 2 incident has sent a torrent of speculation swirling around Chinese politics.

There is speculation that Chinese authorities, panicked by the firestorm of controversy within the Communist Party, tried to sweep the issue under the carpet. There are also rumors that the concert was part of a plot to drive Xi out of power by making him the object of backhanded compliments.

How will Xi react?

Ma Xiaoli herself explicitly referred to backhanded compliments in an interview with Ifeng.com, a Chinese media outlet. Her remarks were so controversial that they have already been deleted.

Ever since the Cultural Revolution ended, breeding personality cults has been considered taboo. Ma noted that any such cult would draw the wrath of and a backlash from the entire Communist Party.

She then accused unidentified persons of laying a political trap by orchestrating something that looked like a personality cult which could be used to attack Xi, who doubles as the Communist Party's general secretary. They "have some ambitions," she said. "We should be alert."

Some of the songstresses from the 56 Flowers (Image from the group's official website)

Ma, who did not identify who might be setting the trap, said the 56 Flowers and the China National Opera & Dance Drama Theater are not to blame.

"It's not that simple," Ma told a Hong Kong newspaper. "No one is allowed to enter a venue like the Great Hall without permission from top officials. These organizers are the ones who manipulate. ... Even [disgraced official] Bo Xilai could not get into the Great Hall. How could they? Where did they get their approval? We must get to the bottom of this."

Ma's remarks show she is alarmed by moves by leftists who supported Bo Xilai, a onetime rival to Xi. She has also leveled her criticism at the Communist Party's Publicity Department.

Since being inaugurated, Xi has been wielding a sweeping anti-corruption campaign against his political foes. The Communist Party's Publicity Department has always been embroiled in the power struggle. The department is supervised by Liu Yunshan, a member of the Communist Party's Politburo Standing Committee, the party's top decision-making body. He is in charge of publicity and ideology.

Liu once worked for Xinhua. He has been close to former Chinese President Jiang Zemin, which makes his relations with Xi delicate. Many figures close to Jiang have been netted in Xi's anti-corruption campaign.

Meanwhile, Liu Qibao, head of the Publicity Department, belongs to the Communist Youth League faction, a massive political force within the Communist Party comprising former officials of the Communist Youth League. This faction has often clashed with the Princeling faction and the second red generation over personnel changes.

Hu Jintao and Premier Li Keqiang have led the Communist Youth League faction. Hu has already retired. Li, who essentially now has the responsibility of holding the faction together, is supposed to be China's economic czar. Yet he actually has no say in economic policy now that Xi has consolidated so much power. As a result, relations between China's top two leaders have soured.

Meanwhile, China's slowing economy and a backlash against Xi's fierce anti-corruption campaign are prying loose the president's grip on the reins of government.

Discipline inspectors from the Communist Party have also launched a probe into the mysterious May 2 incident. How will Xi handle the case? How will the scandal affect China's political future?