Zhang's dossier of Weng Zhenjie's gangland antics - one multimillionaire congress delegate dumping on another - would be remarkable anywhere. But in Chongqing it landed like a bombshell. ''This is the most brutal battle in Chongqing's business community since liberation,'' says a manager at one of Chongqing's largest and well-connected private companies, who knows both protagonists well. This, after all, is the thriving Yangtze River metropolis where China's only maverick leader, Communist Party boss Bo Xilai, has gained nationwide acclaim by reclaiming the streets from the city's mafia. Bo has thrown thousands of lesser ''black society'' gangsters and their Communist Party protectors in jail and executed several, including the vice-president of the Supreme Court. As well as ''striking black'', Bo Xilai has been "singing red" by leading his city in rousing cultural revolution songs. He has launched an ambitious ''red GDP'' campaign to strengthen state ownership, build public housing and accelerate China's (already breakneck) urbanisation by coaxing and pushing peasants off their land. And yet, throughout it all, Weng Zhenjie has managed to grow bigger.

The ascendencies of big brother Weng and comrade Bo reveal the alchemy of power in China today and a signal as to where the country may be heading. Both men have spun astonishingly complex webs of loyalty and patronage through the Communist Party and its red-blood aristocracy. They have exploited every lever at their disposal and chosen their targets carefully. Weng's wealth and reputation grew out of China's military-industrial complex. In the 1990s he left the Peoples Liberation Army to join the Carrier (Kaili) Group, one of two main arms-trading companies of the time. The Carrier Group was controlled by a special kind of "princeling", Ye Xuanning, whom others in that club of communist aristocrats refer to as their ''spiritual leader''. Ye also ran another lucrative enterprise, the liaison office of the General Political Department of the PLA, which was once responsible for exporting revolution across south-east Asia and which still lubricates links throughout Asia's Chinese diaspora. Ye inherited his status from his father, Marshal Ye Jianying. There's no sign that Weng deals directly with the Ye family but he does sit on the boards of several major companies with the family's key financial officer, Li Junyang. Li, in turn, has myriad connections, including through his gambling habits in Macau and the environmental organisation he runs with a brother of the anointed future president, Xi Jinping. With this calibre of perceived backing, Weng leveraged himself into the cockpit of Chongqing's financial system. He confronted and then reached accommodation with the current Chongqing mayor, with his spoils including opaque shareholdings and effective control over the city's most important state-owned securities and finance companies.

Weng began dressing more regularly in Western suits, he obtained a seat on the Chongqing People's Congress and he launched a money-laundering service for the ''grey income'' of dozens of senior officials, according to several local businessmen who know him well. He bought himself more good luck by donating 100 million yuan in ''compensation'' to police who might have been injured in Bo Xilai's mafia crackdown. Even before Bo Xilai began his anti-mafia campaign he stood out as the only publicly charismatic cadre in the Politburo. He is the son of Bo Yibo, one of the Communist Party's ''eight immortals'' who steered the country through revolution and lived long enough to remain influential until the 1980s. Such princeling status bestows a certain self-assurance and is usually a guarantor of political or business success. Bo's first and second wives were also born to the communist aristocracy. His son through his second marriage, Bo Guagua, studied at Oxford before shifting to Harvard last year. Lately pictures have been circulating on the internet showing a princeling courtship between Bo Guagua and Chen Xiaodan, who is also a grand child of one of the Communist Party's ''eight immortals'', Chen Yun. Foreign business and political leaders tend to be struck by Bo Xilai's charm and political acuity or surprised by his reluctance to read briefing notes, in a country where officials routinely memorise their lines. But even those who closely followed Bo's mercurial career have been rendered speechless by the audacity of his tack towards the Maoist left.

Bo spent much of the Cultural Revolution in jail with his family. His father was mercilessly beaten. His mother committed ''suicide'', to use the official term, frequently a euphemism for murder. Suicides, like party verdicts, were tantamount to proof of guilt. If the victims were really innocent they would not have killed themselves, as the logic goes, or the party would not have shot them. In a strange but potentially important twist of modern Chinese history, Bo Xilai has not only imbued his policies and style with a Maoist red but also forged a personal alliance with Mao family members, including those at the front of the Red Guard movement that caused his mother's death. Last year Bo Xilai invited Mao and Jiang Qing's daughter, Li Na, to Chongqing to lead a rousing performance of Cultural Revolution songs. Earlier, the Bo family hosted the wedding banquet for Li Na's son. The co-host was Liu Yuan, son of Liu Shaoqi, who had attended No. 4 Middle School with Bo's brother. Liu's father was Mao's anointed successor until he died of pneumonia during the Cultural Revolution, after being denied medical help in his concrete prison cell.

Xilai and General Liu Yuan have been reaching out to other left-leaning and forgotten princelings and forging and restoring bonds. Bo's political manoeuvrings are taking place discretely, but his policies are there for all to see. China's polarised intellectuals are holding up Bo's ''Chongqing model'' as either the saviour of Chinese socialism or a portent of China's mafia-state decline. ''Chongqing represents a new economic pattern that transcends left and right,'' claims Cui Zhiyuan, a political scientist at Tsinghua University, reeling off a utopian list of achievements including simultaneously nurturing the private sector and growing state-owned assets six-fold in eight years. And Bo's gifts to Chongqing are apparently not confined to economics. ''Chongqing is an experiment to promote more political democracy for the common people,'' says Professor Cui, before acknowledging that he was on the Chongqing government payroll.

And Wang Shaoguang, father of China's resurgent ''new left'' movement, praises Bo for democratic innovations that draw on Chairman Mao's ''mass line''. Left-leaning and patriotic scholars are impressed with Bo sending officials ''down to the masses'' including to live with peasants for a week each year. Liberals, however, have been shocked by Bo's gangster show-trials, jailing of lawyers, skilful propaganda and extra-tight censorship, and especially his displays of state power and Maoist imagery. ''There are few rulers who after uniting the people do not abuse them like pigs and dogs,'' wrote Yang Hengjun, perhaps the most influential pro-democracy commentator surviving on the Chinese internet. From the safety of a temporary Beijing refuge, dispossessed property mogul Zhang Mingyu praises Bo Xilai's ''strike black'' and ''sing red'' campaigns but adds that they will all be for show if the real godfather of the Chongqing mafia remains protected. ''Weng is at the top of the usury chain,'' says Zhang, who has gone too far to turn back now. ''Chongqing cries for water and he opens the tap. He wears a red cap, profiting himself while working for the state.''

Prominent gangsters who used to answer to ''boss'' and ''big brother'' Weng have gone to jail but Weng just keeps on winning. Billions of yuan in seized gangster assets, including the Hilton Hotel, have been transferred into the ostensibly state-owned company, Guotou, which is actually under the control of Weng. BusinessDay asked Chongqing mayor Huang Qifan about his relationship with Weng. Huang stopped, cocked his head, then waved his arm and continued walking. Bo Xilai did not respond to faxed questions. Weng did not answer calls to his mobile phone but he did respond to Zhang's allegations in an interview with a little known publication in Guangdong. ''I'm a military man by training, and have always gone about my business methodically, and care little for what other people say,'' said Weng. ''I believe that innocence is self-apparent and do not see the need to engage in a war of words. I believe that all things become insignificant in the goodness of time, and that time will be the judge of all things. I have been reading some history books recently, and the protagonists of history always meet the resistance of the little people, and always the result is that the evil-doers kill themselves.'' Weng, like Bo, has grown up steeped in the history of emperors from Qin Shihuang to Mao Zedong. In this world, innocence is a quality of the powerful, and the guilty commit suicide.

Weng is confident that Bo Xilai has assessed the balance of power, as he has, and will not extend his mafia crackdown up to the edge of China's princeling-led military-industrial complex. Kong Lingping, 84, a Chongqing resident, was jailed as a ''rightist'' in the 1950s. He has written a book about the torture, starvation and executions he witnessed at the time. As much as he detests Bo's ''revival of the ghost of Mao'' he can also see black humour in his exposing the party's secrets. ''Over 60 years of Communist Party rule law has become useless, the party organisation is uncontrollable and all government power is controlled by the mafia,'' says Kong. ''The party's internal struggles are intensifying and becoming public.'' In factional terms, the Mao-flavoured alliance of princelings centred on Bo Xilai and Liu Shaoqi's son, Liu Yuan, is growing more important as top leaders regroup and realign ahead of next year's 18th Communist Party Congress. President Hu Jintao recently gave General Liu Yuan another key promotion, not long after Liu had promoted one of Mao's grandson's to be the PLA's youngest general. And when Vice-President Xi Jinping was anointed as President Hu's successor, he flew to Chongqing to tell Bo that his ''singing red'' campaign had ''gone deeply into the hearts of the people and was worthy of praise''. Smashing the mafia, Xi assured his host, was ''deeply popular and has brought joy to the people's hearts''.