"Don't ask me whether the bull run has peaked. The stock market will be in an uptrend in the long run," Lin Yuan, who has become an idol for the millions of Chinese who are pouring into the stock market for the first time this year, told Reuters.

A 44-year-old medical college graduate who was born in the poor northern province of Shanxi, Lin says he's turned an initial stake of 8,000 yuan (US$1,045) into assets of well over 1 billion yuan in the last 18 years.

His widely followed, uncompromising optimism may help to explain the market's relentless ascent to fresh all-time highs.

"My principles are simple: I nearly always invest every penny in the market," Lin said in a telephone interview from Beijing late on Wednesday. "To win in the stock market, you must invest everything there for most of the time."

For ordinary Chinese with little experience of financial investing, Lin offers both a rags-to-riches story that promises eventual success, and a clear, optimistic investment philosophy.

Since last year, he has been widely quoted in newspapers and interviewed by China's state-run television. A search for his name on the Internet with Chinese search engine baidu.com turns up more than half a million entries.

His folksy image -- he is an ordinary-looking man, frequently seen wearing casual clothes, with close-cropped hair and a loud, affable manner of speaking, -- contributes to his popularity.

The Chinese media delight in comparing him to Buffett, the legendary U.S. investor. And while the Sage of Omaha may not always be as determinedly optimistic as Lin, there are similarities between the two men's styles.

Lin says he's continually flying around China to dig into the real performance of companies -- matching Buffett's principle of identifying sound firms in businesses that one understands.

"I only buy companies which I have researched for at least three years, and which have a clear, single core business," Lin said.

Like Buffett, Lin focuses on a relatively small number of stocks. He says he holds about two dozen, including traditional liquor maker Kweichow Moutai Co., China Merchants Bank and Shanghai International Airport.

He started to buy Moutai shares about four years ago at around a quarter of their current market price of around 100 yuan. He now has more than 10 million shares, making Moutai his single biggest holding and leaving him with a paper profit that may total some 750 million yuan, according to Reuters calculations.

Lin began investing in stocks in 1989, as a low-ranking museum employee in the southern boomtown of Shenzhen -- before China had fully embraced a market economy, and before the launches of the Shanghai and Shenzhen exchanges in 1990 and 1991.

He weathered two big market crashes, giving him the confidence to stay bullish on Chinese stocks even as many foreign financial figures warn of a dangerous bubble -- including former U.S. central bank chief Alan Greenspan, who said on Wednesday the market was heading for a "dramatic contraction".

Though Chinese officials have also expressed concern that the market may be overheating, Lin's emphasis on long-term investment -- rather than the short-term speculation which has mushroomed during the bull run -- makes him useful to government policy.

The government is keen to create an equities culture in China, to give ordinary households a place other than bank deposits to put their savings, and to develop the stock market into a viable fund-raising source for companies.

Lin's bullishness may seem extreme with the market already at stratospheric levels, but in many ways he remains the perfect poster boy for equities.

"Persistent long-position holding has made me lose no money in any single stock," Lin said. "My aim is profits -- profits in every single investment."