To most Beijingers, the receipt the attendant gives them for the six cents paid to use the public toilets in the subway is a worthless piece of scrap, quickly crumpled up and thrown away.

To Hao Jinsong, that piece of paper is a seed of Chinese democracy.

It took the 35-year-old law scholar a court battle to force the subway authorities to issue the legally required receipt, and he still treasures the one he sued for. But the chit itself, he says, is not important.

"Behind this receipt is a law that gives people the right to ask for one," he explains. "If nobody respects the dignity of the law, everybody loses his own dignity. If today you lose your right to a receipt, tomorrow you may lose your right to your land, your house, your freedom, and even your life."

Hyperbole? In a country where the rule of law is very much a work in progress, and where the ruling Communist Party routinely dictates judges' verdicts in sensitive cases, Mr. Hao's passionate faith in the law might seem naive.

But it is the very weakness of the rule of law in China that inspires his crusade, he says. If "people don't use legal recourse to defend themselves because they think it's useless ... the law grows even weaker," he argues.

"When ... people use the law as naturally as they use chopsticks, China will be close to democracy," he adds.

Hao is a pioneer of public interest lawsuits, a growing trend in a country where they were unknown, or dismissed by judges out of hand, only a few years ago.

He and a swelling band of lawyers like him have attracted less international attention than legal activists whose efforts to defend human rights have earned them beatings, house arrest or jail terms.

But they are achieving prominence in China, and winning plaudits from their peers. "We need someone to stand up and challenge shortcomings of institutions," says Wu Ge, a law professor at Beijing's Tsinghua University.

Hao is best known for lawsuits he has brought against the powerful Ministry of Railroads, challenging its refusal to give tax receipts for goods bought on trains, and its ticket pricing policy.

He won the receipt case, on his third attempt, earning the government $2.7 million a year in tax revenue from the railroads. And though he lost two court battles to stop the railroad management raising ticket prices during the Spring Festival, when 150 million Chinese go home for the holidays, his campaign attracted wide public support. Management bowed to the pressure, and has left holiday ticket prices untouched for the past two years.

That, says Yiyi Lu, a researcher at the Royal Institute of International Affairs in London who has written a study of public interest lawsuits in China, is an example of how "you don't need to win the case to win the cause."

Key to such victories has been media coverage and the public debate it provokes. Though Chinese newspapers don't dare report court cases involving political dissidents, many of them – including the Communist Party's mouthpiece the People's Daily – have written approvingly about Hao's cases.

This would not happen if Hao confronted the government head on over issues such as free speech. Instead, he deliberately restricts himself to less political cases, holding the government's feet to the fire on a goal it has publicly set itself – the rule of law.

"I would like to say the government and I are going forward together," he explains. "I don't want to strip the government of its power, but to curb it."

Achieving that goal starts with citizens knowing their rights and defending them in court if need be, Hao says. "Ordinary people have to change into independent- minded citizens before China will be strong," he argues.

Even independent-minded citizens, however, could be forgiven for steering clear of political action when they see what happens to the few who publicly demand an end to one-party rule in China.

A proponent of gradual change, Hao insists that democracy can only be won "at the right pace.

"It's like a running track," he says. "A few of the elite are leading the pack, but if ordinary people see that the track leads to jail they won't dare to get on it. My way is a way ordinary people can imitate" by going to court to defend their rights as consumers.

"When they realize they have rights," Hao hopes, "they will call for other rights, like freedom of speech or publication, later."

Fewer than 20 percent of Chinese public-interest lawsuits end in even partial success for the plaintiffs, according to a 2006 study by legal scholar Huang Jinrong. But that does not daunt Hao.

The public attention that such cases attract raises public awareness of the uses of the law, he says, and with each case "we change officials' attitudes."

Li Heping, a lawyer whose human rights work has earned him a round-the-clock police shadow and who was kidnapped and beaten up last year, also believes the sort of work Hao and his colleagues do is helping to change China.

"Each bit of progress has to be made step by step," he says. "It takes a lot of people working from different perspectives."

Hao is currently engaged in a suit against the National Forestry Agency, which he accuses of refusing to investigate a false claim by the Shaanxi provincial authorities that a South China tiger, thought to be extinct, had been photographed. The incident drew massive interest on the Chinese Internet, and widespread criticism of the authorities for trying to create a lucrative tourist attraction out of a faked photograph.

The lawsuit, Hao says, is designed "to show people that the government does not have the right to say whatever it likes. The government cannot lie, and ordinary people have the right to unmask the government's lies."

Such cases may not shake the world, but "they have a cumulative effect," says Dr. Lu. "When lots of people bring them, they contribute to positive change."

"Today I am just a butterfly flapping my wings in the Beijing sky," says Hao. "But in 20 years there will be a storm in the whole country."