BEIJING - Microsoft Corp. co-founder Bill Gates and billionaire investor Warren Buffett plan to sell the art of giving to China's super rich in a visit later this month that's already sparked some soul searching among the world's second-largest number of billionaires.

Reactions to Gates and Buffett's trip have been swift and varied: One prominent Chinese philanthropist quickly pledged his entire fortune to charity, while the head of a private foundation said Chinese businesses should be leery of emulating American-style charity donations before essential corporate standards such as workers' rights are improved.

Many have pointed to shortcomings in China's charity system, which critics say lacks transparency. The discussion underscores what experts say is the relatively immature state of philanthropy in China, where in just three decades economic reforms pulled hundreds of millions out of poverty and created a generation of newly minted millionaires.

Gates and Buffett have been campaigning to persuade other American billionaires to give most of their fortunes to charity and hope to spread the idea on a trip to China later this month. Their campaign includes a private dinner in Beijing Sept. 29 with a group of wealthy Chinese -- and some are wary.

A "small number" of the more than 50 invited guests called to ask if they would be required to pledge a donation at the dinner, said Jing Zhang, press officer of the Bill & Melinda Gates Foundation. But Gates and Buffett just want to talk, Zhang said.

Still, that hasn't stopped one of their guests, multimillionaire philanthropist Chen Guangbiao, from declaring in an open letter to Gates and Buffett that he would donate all of his fortune upon his death.

"I'm a rich man, but I don't want to be a miser," Chen told the Associated Press.

Chen, 42, a peasant-turned-chief executive of a renewable resources and recycling company in Jiangsu province, has an estimated fortune of 3 billion yuan ($440 million) and is ranked 340th on the 2009 Hurun list of China's wealthy.