Being a relatively new city in China, Shanghai does not really have a cuisine of its own, but successfully refines all the work of the surrounding provinces such as Zhejiang and Jiangsu. Through years of culinary practice and the assimilation of the art in other styles of cuisine, Shanghai chefs have also created a style of cuisine peculiar to the region. Shanghai dishes are usually characterized by the use of heavy and highly flavored sauce.
The use of sugar is another uniquness found in Shanghainese cuisine and, especially when used proportiaonally with soy sauce, the taste created is not so much sweet but rather savory. My chef friend told me that this is mainly due to the fact that sugar neutralized the sourness found in soy source. Household in Shanghai would consume as much soy source as sugar. Visitors are often surprised when the "secret ingredient" was revealed by local Shanghainese.