Recently, Wang expanded the most scenic outlet, in glorious Ritan Park, where the upper terraces overlook a 500-year-old altar used for sun-worshipping ceremonies by the Ming and Qing emperors.

While the view is a factor in choosing that particular branch of Xiao Wang, the main reason for going is the food. There are more than 200 dishes on the menu, including the classic Peking duck. Among the most popular are Beijing staples such as yu xiang rou si (fried shredded pork with ginger garlic, vinegar sugar and red chilli oil), gan bian si ji dou (deep-fried French beans with minced pork), tie ban chi jiao niu rou (sizzling beef slices with pepper and onion in a black bean sauce) and piao xiang pai gu (deep fried pork ribs with salt and pepper).

'I am the executive chef. I control everything in my kitchen - the quality of the dishes and the raw materials,' says the affable Wang, 46, who began his career as an executive with British Aerospace before the entrepreneurial bug bit.

When the first Xiao Wang opened, the owner was already a dab hand in the kitchen.

'My mum is from Sichuan province, and every meal we had was delicious, even though we were not rich,' Wang says.

'I learned from her when I was a little boy. I would ask my father to buy the ingredients and ask my mum to prepare them. When everything was ready, I stirred ingredients in the pan, and when I had finished, I would ask my sister to place the food on the serving dish.'

After graduating with an economics degree, he snagged a job with British Aerospace, selling its aircraft to fast-expanding mainland airlines. It provided a decent salary and some keen insights into the corporate way of doing business. It also gave Wang the urge to run his own show.

'I thought it was time to do something on my own,' he says. 'I didn't really like the company corporate life, sitting in the office for the whole day. There was not that much choice back then if you wanted to run your own business: I liked good food, so it seemed logical to start a restaurant business.'

That first restaurant was in a building close to the city's embassy district. To lure expatriates as well as locals, Wang used his English-language skills to draw up a menu that listed dishes in English and pinyin, giving overseas guests the option of having a stab at ordering in Chinese. It made Xiao Wang an expat favourite even then.

'The menu itself was very important because people who don't speak Chinese can read it out loud and staff can understand. People from overseas say it is the most convenient menu they have ever seen.'

The capital's most renowned dish, Peking duck, found its way onto the menu only by popular request - and has proved to be one of the more time-consuming dishes to make. The boss claims that preparing it is more trouble than it's worth, but up to 50 are sold each day, so it remains on the menu.

That and other dishes certainly draw in the crowds. On any one night, the expanded Ritan Park operation might have tables of diplomats entertaining their guests, a group from the Chanel fashion house with visiting Paris-based executives in tow, and cadres drinking shots of potent rice wine to the noisy accompaniment of frequent cries of ganbei.

To help make expatriates feel at home, Wang hired an English-speaking German ma?tre d', Holger Heckl, and tries to ensure the waiters have a rudimentary command of English. The restaurant is not on the tourist trail, although the odd guidebook-clutching guest does find Xiao Wang's and is usually amazed to discover a local-restaurant menu that lists tasty dishes in grammatical English.

In fact, the menu has become something of a conversation piece - and a revenue earner. Some guests like the parchment scroll list of dishes mounted on a wooden pole so much, they ask to take one home, which they may do for HK$1,100.

Most of the 200 or so menu dishes are well under HK$100, allowing diners to order liberally and drink copious amounts of draught beer for less than HK$300 a head.

Wang has branched out, now also running a tour agency that organises city bus tours and a bicycle hiring service. But clearly, the restaurant interests him the most, as he likes to meet and greet diners.

Xiao Wang is a particular favourite with families, as it offers plenty of space for youngsters to run around. Ritan Park itself is also a popular weekend spot for people with children: a common expatriate excursion is to visit the playground, walk around the lake, have a drink at the waterside Stone Boat Bar and top the day off with a feast at Xiao Wang's.

'We have a lot of kids, which makes me happy,' Wang says. 'It means we have future guests!'