Oyster sauce describes a number of sauces made by cooking oysters. The most common in modern use is a viscous dark brown condiment made from oyster extracts, sugar, salt and water thickened with corn starch. Oyster sauce is an accidental invention. It was invented in 1888 by Lee Kum Sheung, a Chinese chef who was working in Hong Kong.

In 1888, Lee Kum Sheung was busy running his food stall in Nanshui – a neighbourhood to the south of Zhuhai in modern day Guangdong province. As usual, he set a big pot of oyster soup on the stovetop and left it simmering gently, ready to feed his lunchtime customers. What it was that distracted him from his stove we will never know, but he promptly forgot about his oysters. When he discovered them many hours later, still simmering away on the hob, they had reduced to a thick brown paste – certainly not the clear soup that his customers were expecting. He tasted the sauce and was surprised to find that it was delicious – he had invented the world’s first oyster sauce.

Lee spent his evenings refining the sauce before he began to sell it. His new sauce became popular all over the district, spreading to the neighbouring cities of Jiangmen, Zhongshang, Guangzhou, and Macao. He put the name Lee Kum Kee above his shop; later became the leading sauce manufacturing company in China and Asia.

The accidental discovery of the flavorful sauce led to the development of what is now known as oyster sauce. It became popular in Chinese cuisine and eventually spread to other parts of Asia and the world. Oyster sauce is made by simmering oysters in water and extracting their essence, which is then combined with other ingredients such as soy sauce, sugar, and sometimes additional flavorings like garlic or ginger.

Lee Kum Sheung's oyster sauce was a major innovation in Chinese cooking. It was the first sauce to be made from oysters, and it gave chefs a new way to add flavor to their dishes. Oyster sauce is now used in a wide variety of dishes, including stir-fries, noodles, and seafood dishes.

According to greatbritishchefs.com & Wikipedia & macaomagazine.net