The woman was still wearing her kitchen apron when Chen Si spotted her on the Nanjing Bridge.

By the time Mr. Chen raced across four lanes of traffic, the woman had already started climbing the narrow railing separating her from the surging waters below.

"After I yanked her back, all she did was cry," said Chen, who is all too familiar with such scenes: The burly man has spent practically every weekend of the last four years patrolling this stretch of roadway above the mighty Yangtze River, looking for signs of human despair.

Chen is a self-appointed lifeguard on the so-called Chinese bridge of death. His record so far, he says: 144 lives saved.

Not bad for a one-man crusade.

Here in this ancient capital, everyone knows the Nanjing Bridge. Since it opened nearly 40 years ago as a symbol of Chinese Communist might, an estimated 1,000 people have killed themselves by leaping from the span.

"I look for people filled with a sense of gloom and doom," Chen said as he scanned the blur of cars and trucks humming over the bridge, squinting through his binoculars for people apparently preparing to commit suicide.

Not all his efforts have been welcomed, at least initially.

"I told him to go away, it's none of your business," said Shi Xiqing, recalling the day Chen saved his life. Mr. Shi, who collects recyclables for a living, was deep in debt. "I couldn't handle it anymore," said Shi, now a close friend of his savior. "I went to the bridge because it's convenient – a few seconds, it'll all be over."

Most people Chen helps don't want to stay in touch. But Shi was different. He liked how Chen would never say no to handing over yet another small loan to tide him over. Chen never tired of telling him that everything was going to be OK.

"This bridge needs people like him," Shi said. "Without him, I would not be here today."