Much like Lok Ma Chau, further to the east along Hong Kong's frontier, Lau Fau Shan was one of those places, back in the mainland's pre-'economic liberalisation' days, that visitors came to for a glimpse of forbidden, forbidding Red China. Unlike Lok Ma Chau, which had a fortified police station, a hillside lookout post, numerous tatty souvenir stalls but not much else, Lau Fau Shan was well-known for its seafood restaurants, especially those whose menus featured the local product - oysters. Oyster production has been a Deep Bay speciality for centuries - documented cultivation in the area dates back as far as 1727, when the Ha Tsuen family firm Yu Kung Tong secured the right to cultivate oysters around Lau Fau Shan. The practice was probably in place for centuries before that. Immature oysters spawned at Lau Fau Shan were taken upriver to Tung Koon (Dongguan) and Sha Ching to grow to maturity but this activity ceased - officially, anyway - with the Communists' assumption of power in 1949. The resultant United Nations embargo on trade with the mainland greatly expanded Lau Fau Shan's oyster production industry; for the next three decades most of the oyster sauce consumed in Chinese restaurants across the United States was produced here. Oyster shells also have their uses; ground up they are a prescription item in traditional Chinese medicine - mostly as a calcium supplement - and are used as a poultry-food additive for the same purpose. Until industrial-scale commercial concrete became cheap and easily available in Hong Kong in the late 19th century, oyster shells were burnt in lime kilns at Chek Lap Kok, Peng Chau, Tai Po and elsewhere to make a primitive Portland cement. Contemporary Hong Kong has little use for oyster shells and slowly rotting middens of discarded shells can be seen scattered along the Deep Bay foreshore. The incredibly under-used Deep Bay bridge can be seen from Lau Fau Shan. Built at massive public expense, the structure links Hong Kong and Shekou. Lau Fau Shan still has a number of unpretentious seafood restaurants of reasonable quality, tucked away down the village's grotty side lanes. Like many other venues in Hong Kong, most live seafood sold here is imported, sometimes from as far away as Mauritius, the Seychelles and Fiji. As for the oysters, well, they are still produced in considerable, but declining, quantities in Deep Bay's heavily polluted, sewage-rich waters. Only a fool would eat them raw. Cooking greatly reduces the incidence of an acute gastrointestinal episode but does nothing to eliminate heavy metals, dioxins, pesticide residues and other contaminants. This is Hong Kong, remember - Asia's renowned food paradise.