Gyōza in Japanese Chinese cuisine are listed as deriving from which Chinese regional cuisine?

In the article, Japanese gyōza are listed as deriving from Northeast Chinese cuisine.

Northeast Chinese cuisine comes from the region historically known as Manchuria, including modern Heilongjiang, Jilin and Liaoning. Its food traditions reflect Northern Han, Manchu and Korean influences, with wheat-based staples such as noodles, steamed buns and dumplings playing an important role in the local diet.

The connection is also tied to twentieth-century history. The Japanese gyōza tradition developed from recipes encountered in China and brought back to Japan by Japanese colonists and repatriates after World War II. Japanese cooks then adapted the dumpling to local tastes and restaurant habits.

Japanese gyōza are most often pan-fried, producing a crisp bottom while steaming the upper wrapper. They can also be boiled or deep-fried. This differs from the broad Chinese category jiaozi, which includes many regional fillings, shapes and cooking methods; gyōza is the Japanese adaptation, not simply a synonym for every Chinese dumpling.