Jiaozi was made of wrapper of wheat flour and filling. Man can use any food material to make filling. Mostly Jiaozi-filling is made of meat and several kinds of vegetables. Jiaozi-wrapper is thin and soft, and the filling is rich in taste. Even today most Chinese still think jiaozi is the most tasty Chinese food.
Chinese have already almost 2000 years' history of eating Jiaozi. Jiaozi was created by an famous Chinese doctor, Zhang Zhongjin (about 150 - 215), in East-Han dynasty. He saw that many poor people got cold-injury in their ears in winter and decided to help them. Han made a medicine with mutton and some herb-medecine, and packed the medicine with thin wrapper made of wheat-flour dough. To get more attention, he made the food in the form of ear and called it as "soft ear". Soft ear pronunciated in "Jiao Er" in Chinese. This pronunciation is similiar with "Jiao Zi". It is not impossible that the custom of eating Jiaozi at Zi-time was developed with inspiration getting from the pronuciation of the name "Jiao Er". He provided the food free to the poor and had helped many. Because jiaozi was very tasty, it became a kind of common food very soon.
Although it looks complicate, it is actually very easy to make Jiaozi. Man only needs to divide the wheat flour dough into small parts, make each part flat and some round with a dough stick and pack some filling with the wrapper. The wrapper is thin and soft, so it is very easy to be wrapped together and formed to the expected form. In northern China, small children started to learn making Jiaozi when they are 3-4 years old. For them making Jiaozi with the adualt is just a funny game. It is a common family entertainment in northern China that family members sit together and make Jiaozi. They often competite who is the cleverest on making Jiaozi to increase the fun. Such a happy scene probably is also a reason people in northern China choose jiaozi as a necessary Chinese New Year food.